VPART Pest and Scouting Report

Hi all,

Now that we are in the dogdays of summer, fields look lush and harvest season is fully underway. That lushness, however, also provides potential for the buildup of diseases and pests that can easily hop from farm to farm throughout the region.

One of the concerning updates in the region are reports of late blight in several surrounding states. We are getting reports from western New York and some areas south of Vermont that late blight may be on its way. Despite this concerning news, the silver lining is that we have not heard of any confirmed sightings in Vermont, yet.  However, with some weather systems moving in from the west over the upcoming days, the incidence line may creep a bit closer. So, it is still important to monitor your tomatoes and potatoes for any sign of late blight. Common symptoms on tomatoes and potatoes are greenish-brown lesions on leaves and stems, that are often water-soaked and may be accompanied by white fuzzy fungal growth. These symptoms often come from the top of the plant downward, as the spores are transported via overhead rain. It is especially important to monitor for potential infections after a heavy rain. If you suspect that you may have late blight, be sure to destroy any infected plants as soon as you are confident in your diagnosis. Late blight requires living plant material to survive, so destroying any living infected material will reduce the likelihood for spread to other areas on your farm or neighbors. We’ve been lucky to avoid any outbreaks over the last few years, but we still must be vigilant.

In addition, other diseases to watch for are cucurbit downy mildew (CDM) and basil downy mildew (BDM). There are reports of potential CDM infections in the southern part of the state and areas to the west. Neither of these mildews overwinter here; instead, they arrive with storm fronts from the south. CDM often devastates late cucumber plantings in Vermont, appearing either later in the season or during active storm periods. CDM exclusively affects cucurbit plants, typically starting on older leaves and spreading to younger ones as the infection progresses. As symptoms worsen (via sporulation), the lower leaf surface develops a light grayish-purple “downy” appearance. Lesions can merge, leading to extensive tissue death and exposing fruit to sunscald. Severe infections can cause significant defoliation. Opting for resistant cultivars is the best defense, though conventional fungicides are effective. More information and images are available here: https://ag.umass.edu/vegetable/fact-sheets/cucurbits-downy-mildew

Basil Downy Mildew  (BDM) has been reported in Maine and potentially in other nearby states. Similar to CDM, once established in a field is very hard to manage. It really becomes a situation of damage control, getting rid of any diseased plants in the hopes of saving healthy plants. The reality is, once an outbreak takes hold, there is not much that can be done other than the removal of diseased material.

Also, if you missed Meg McGrath’s recent listserve posting related to BDM research, please refer to the announcement below, as it will help plant breeders to stay informed on the evolution of the disease and its effect on our resistant varieties:

“Researchers at Rutgers (who are part of an international team addressing this) are asking anyone who observes basil downy mildew on their plants in the USA and Canada to send infected leaf samples and to report occurrence to the following website: https://basil.agpestmonitor.org/. These samples will be used to better understand the existing pathogen populations and help drive solutions towards the downy mildew problem. This problem cannot be solved alone! Thank you!!

Shipping Instructions:
Please collect as many infected leaves showing sporulation (or classic yellow leaf banding of this disease) as possible and wrap in a dry paper towel before placing inside a quart-sized ziplock bag. Seal the bag partially (leaving about a quarter open) before placing in an envelope with

Piece of paper with sample source address, basil variety if known, and contact information (email, phone number) in case there are questions about sample.

Mailing Address (regular mail fine as just pathogen’s DNA needed; not live pathogen):
B.A.S.I.L.
Foran Hall, Rm 392
59 Dudley Rd

Rutgers University
New Brunswick, NJ 08901”

Please address any questions or concerns you may have to Rob Mattera (robert.mattera@rutgers.edu)

 

As far as insect pests, it seems to be more of the same.  Here are a few important notes of those pests.

• Onion thrips populations are really picking up with the dry, hot temperatures. However, the slow buildup earlier this season due to consistent rains has meant there has been little impact on yield so far. Despite seeing increasing damage now, most onions on our monitoring farms are looking great.
• With the extended heat before this recent cooling, Colorado potato beetle populations have shifted so that most of what we’re seeing now are adults emerging from pupation. This may create a good opportunity for potatoes to bulk up without heavy larval pressure. Remember that after flowering, potato plants can tolerate quite a bit of defoliation without significantly impacting yields.
• Lots of our moth pests: armyworms, corn earworms, cutworms, etc, are beginning to show up in increasing numbers in traps and crops in the region. If you have struggled with these in the past, you might want to start scouting for their damage.
• Leek moth trap numbers in most areas are nearly zero, as populations are mostly in the larval stage. You are likely to see damage in your onions and shallots growing over the next week or two. It’s probably fine to remove your exclusion netting on onions, if you are planning to harvest before the next flight (mid August)
• Cabbage whites, aka imported cabbage worm, are showing up in high numbers on lots of farms. For organic growers, Bt and spinosad sprays can be effective, though Bt tends to be more useful while caterpillars are smaller AND it requires the caterpillar to ingest it.

 

As always, our website for the scouting reports can be found here. In addition to the pests reported here, our website also has a more comprehensive list of pests. The list also documents the progression of many common pests as they emerge throughout the season.

For detailed management information about these pests, as well as a comprehensive guide to current  production and pest management techniques for commercial vegetable crops, check out the  New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions.

 

Pest	Crop	Observations
Striped Cucumber Beetle	Squash, Cucumber	Even though numbers are still very high, we are not seeing a ton of bacterial wilt.
Squash Bug	Squash	Lots of pressure, adults, nymphs are prevalent!
Colorado Potato Beetle	Potatoes, Eggplant	Populations are mostly adults and eggs. This may provide some time for potatoes to bulk up.
Flea Beetle	Potatoes, Eggplant	Very low numbers, they are not fond of heat.
Leek Moth	Onions, Garlic	Few if any adults in traps.
Thrips	Onions	Thrips are growing and damage is also more prevalent, but onions seem to be bulked up enough to tolerate the pressure at this point.
Cabbage worms	Kale	Seeing a really big spike in Imported Cabbage worms
Potato Leafhoppers	Potatoes, Beans	We are seeing some fields with PLH, but the pressure seems really low in most cases.
Tarnished plant bug	Strawberries, potatoes	Tarnished plant bugs are now being seen in various crops and some outbreaks are being reported.
Mexican Bean Beetle	Beans	Definitely a growing concern in beans on some farms, be on the look out
Swede midge	Brassicas	Very limited outbreaks thus far on most farms.

 

Hi all,

High temperatures continue to put a lot of stress on plants, leading to symptoms that can take many forms and may be mistaken for diseases. When contacting the diagnostic clinic, be sure to include observations about where and how the issue appears across your planting. This information will help their team more accurately diagnose the problem.

This week we are starting to see a few peaks in pests that have taken a bit longer to build up than the last couple of seasons. One pest that we are now starting to see in greater numbers is the squash vine borer, both in our traps and in plants. While they are often spotty in their distribution in a field, a large population can be quite problematic. The first signs of the pest will often be wilting, which may make you think of bacterial wilt transmitted by striped cucumber beetles. If you start to see some plants wilting in the field, look at the base of the plant and check for any stem damage or some of the insect excrement, also known as frass. That will be the tell for the presence of the pest. If the plant is not completely wilted, it is sometimes possible to do some quick removal of the larvae inside the vine with a knife and some delicate surgery. Once removed, you can try to bury the damaged part of the vine with some soil. If there is enough of a connection left, things may be possible to save.

Leek moth numbers have waned enough on most farms that it is likely safe to start removing any exclusion netting if you have been keeping alliums protected. With garlic harvest in full swing in most areas, be sure to look for the beginning of any larval feeding in the neck of garlic before bringing them into curing and storage areas. Our research has shown that most marketable damage to garlic from leek moth occurs when eggs or larvae hitchhike on the stems and feed down into the bulb as the neck dries down. Topping garlic and/or onions before curing or storage can significantly reduce the risk of post-harvest damage from leek moth in areas with large populations. That said, it is also looking like onion harvest might miss the next flight of leek moth!

Colorado potato beetles are really thriving this year. While high CPB numbers are no surprise in July, we are receiving numerous reports from organic growers about the emergence of spinosad resistant populations. With the loss of the Bt strain for CPB control and a lack of other potential organically approved chemical options, it was just a matter of time before resistance would crop up.

Our team continues to test the efficacy of some organically approved biopesticide options, particularly fungal sprays and some innovative new conventional options. We will keep you posted on the outcomes of those studies. In addition, we are again seeing good results with our delayed planting study. Our late June and early July plantings are showing greater vitality compared to the earlier May plantings, which are mostly sticks at this point. Finally, there are lots of growers using various tractor and human powered whacking and collecting methods. If folks would like to share their methods, it might be useful to collect those suggestions for a VVBGA post, a twilight meeting, or our upcoming UVM Catamount Farm and Field Day (see below).

Regional Roundup:

• Though we are yet to hear of any confirmed incidence of cucurbit downy mildew in cucumber or melons within Vermont, it is just a matter of time, as it seems to be around within the region (e.g. NY, CT).
• Corn earworm, aka tomato fruitworm, is being found on farms in Vermont, with reports of larvae in peppers and tomatoes nearby cornfields. Trichogramma parasitoid wasps can be an effective strategy if timed right.
• Maine is reporting incidence of Basil downy mildew, so be on the lookout in any non-resistant varieties.

 

Finally, as referenced above,  we wanted to put on your radar an upcoming event at the Horticultural Research and Education in South Burlington:

HREC Farm and Research Field Day

When: August 13, 2025

Time: 2-5pm

Location: Horticulture Research and Education Center (HREC), 65 Green Mountain Dr., South Burlington, VT

 

UVM’s Catamount Educational Farm, in collaboration with the Department of Agriculture, Landscape, and Environment (ALE), is excited to host a Farm and Research Field Day at the Horticulture Research and Education Center (HREC) on Wednesday, August 13, from 2:00 to 5:00 PM.

 

We hope you’ll join us for an afternoon of sharing, learning, and connecting with all the research, farming, and outreach happening at the farm!

 

The day will include:

• Catamount Farm Tour – Explore and learn about the food production systems, educational initiatives, and community partnerships occurring on the farm.
• Field Research Tour – Check out the innovative research projects currently underway at HREC for a host of research projects for vegetable, fruit, and other specialty crop growers.
• Informational Exhibits –

Full Schedule will be sent to registrants and posted to various listservs as the date nears.

 

This is a great opportunity to connect directly with the diverse group of people working at the intersection of farming, teaching, and agricultural research.

 

Though registration is not required, if you plan to attend, please submit your name to this form.

 

Any Questions? Contact Vic Izzo (vizzo@uvm.edu) or Terry Bradshaw (tbradsha@uvm.edu)

 

For detailed management information about these pests, as well as a comprehensive guide to current production and pest management techniques for commercial vegetable crops, check out the  New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions, using our new submission form and/or directly emailing me at vizzo@uvm.edu

 

Pest	Crop	Observations
Striped Cucumber Beetle	Squash, Cucumber	Even though numbers are still very high, we are not seeing a ton of bacterial wilt.
Squash Bug	Squash	We are beginning to see nymphs, as eggs begin to hatch, but most of the populations are in the egg stage.
Colorado Potato Beetle	Potatoes, Eggplant	While there are overlapping generations that this point, most larvae that we are seeing are getting ready to pupate in the soil.
Flea Beetle	Potatoes, Eggplant	Very low numbers, they are not fond of heat.
Leek Moth	Onions, Garlic	The most recent flight is beginning to wane, as the population moves into its larval stage.
Thrips	Onions	Thrips surprisingly are being found at lower numbers compared from previous years.
Cabbage worms	Kale	We are seeing some diamondback moth on some farms. Other cabbage moth caterpillars are present but not causing much damage.
Potato Leafhoppers	Potatoes, Beans	We are seeing some fields with PLH, but the pressure seems really low in most cases.
Tarnished plant bug	Strawberries, potatoes	Tarnished plant bugs are now being seen in various crops and some outbreaks are being reported.
Mexican Bean Beetle	Beans	Definitely a growing concern in beans on some farms, be on the look out
Swede midge	Brassicas	We are seeing outbreaks of SM on some farms but others are completely untouched. Damage is mostly in broccoli and collards.

 

 

 

 

 

Hi all,

Our scout team was on a bit of a break last week, so this report is coming together with a bit of a gap from our last report.

With July upon us, the heat is welcome, but too much of a good thing can become a problem, and this heat is no exception. We’re seeing and hearing reports of significant heat stress symptoms in many crops, especially those grown in high tunnels or other protected systems. The combination of heat and humidity can also make it tricky to tell whether symptoms are due to disease or environmental (abiotic) stress.

One helpful strategy for telling the difference is to look at how the damage is distributed in the crop. If symptoms start in one area and spread outward, it’s likely a disease. If they’re evenly distributed across a section or the whole crop, an environmental factor is probably to blame. And if the damage appears randomly or in a more scattered pattern throughout the planting, it could be the work of a mobile pest like a flying insect.

As far as insects are concerned, we continue to see swede midge damage showing up on several farms. Most of the damage right now is in broccoli and Red Russian kale. The higher pressure in Red Russian isn’t a complete surprise, as our team has identified a particular preference by swede midge for this variety. If you’ve historically had issues with swede midge, it might be wise to steer clear of Red Russian kale.

If you’re planting a fall crop and are already seeing damage in your summer brassicas, you might want to consider using exclusion netting if that’s feasible for your scale. Also, keep in mind that midges can remain in the soil and emerge up to two years after an infestation, so plan your rotations accordingly if possible.

In addition, the Chen Lab at the University of Vermont is looking for growers dealing with swede midge to participate in a study exploring new nonchemical management strategies. If you’re interested, you can email our team directly and we will connect you!

Several growers have reached out to our team to inquire about the current status of Spotted Wing Drosophila (SWD) within Vermont. Our current SWD monitoring program across three counties has been quiet, as we have seen very limited numbers of SWD within our traps. With blueberry picking season beginning, we expect to see increasing SWD trap counts over the next couple of weeks. We will keep you posted on our traps. For those asking about which traps are best for monitoring, we’ve been having great success with the Scentry lures and traps. They seem to outperform most of the trap/lures that we’ve used over the years.

Regional Roundup:

 

• We have begun to see some Mexican bean beetle pressure on farms and that is a bit later than in previous seasons.
• Colorado potato beetle populations are mostly in their later stages and beginning to pupate in the soil. Folks planting late, may benefit by planting a crop asap, for seed potato at least
• Onion thrips are beginning to build, but the consistent rains have been a help on many farms.
• Diamondback moth is around and causing some damage on select farms.
• Western bean cutworm is being found in traps in NY and NH. Likely around in VT.

 

For detailed management information about these pests, as well as a comprehensive guide to current production and pest management techniques for commercial vegetable crops, check out the  New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions, using our new submission form and/or directly emailing me at vizzo@uvm.edu

 

Pest	Crop	Observations
Striped Cucumber Beetle	Squash, Cucumber	Beetles are beginning to be found in much larger quantities. Plants don’t seem to be particularly damaged.
Squash Bug	Squash	Mostly adults and  eggs.
Colorado Potato Beetle	Potatoes, Eggplant	Seeing lots of larvae and high pressure in most potato plantings. Most larvae are in the last stages before pupating in the soil below plants
Flea Beetle	Potatoes, Eggplant	Low numbers of flea beetles but damage has been done in most crops. We’ll likely see a lull for the next few weeks as the temps pick up and first generations are pupating.
Leek Moth	Onions, Garlic	VERY high pressure in some plantings. Finding lots of adults in traps, so adults are laying eggs right now in the region. We estimate that we are just past peak in most areas of Vermont. Adult captures should be waning soon. Also it seems that the distribution of Leek moth is being found in new areas in the region, particularly NH.
Thrips	Onions	Thrips surprisingly are being found at lower numbers compared from previous years.
Cabbage worms	Kale	We are seeing some diamondback moth on some farms. Other cabbage moth caterpillars are present but not causing much damage.
Potato Leafhoppers	Potatoes, Beans	Some spotty distribution of adult leafhoppers in potato fields. Aren’t seeing any leaf burn.
Tarnished plant bug	Strawberries, potatoes	Tarnished plant bugs are starting to pick up in some crops
Mexican Bean Beetle	Beans	We are seeing bean beetle larvae in some plantings causing some extensive damage on some farms.

 

Hi all,

 

I hope things are going well out in the fields as the temperatures begin to really heat up over the next week or so. With high temps come faster generations and more insect outbreaks.

 

We have some new discoveries this past week of some important pests that are just beginning to be found on farms.

The first spotted wing drosophila (SWD) adult fly of the season was just captured in one of our traps. The good news is that it was only one fly, found in just one of the ten traps. This low level of trapping activity is similar to what’s being observed across the region, so it looks like we’re at the beginning of the SWD season. We’ll keep you posted as the season progresses. For those who want to monitor SWD directly on their own farms, we’ve had great success with the Scentry SWD lures and traps, although they can be a bit pricey. In previous years, we’ve used a diluted grape juice solution for trapping, and that seems to work well too. That said, we’ve generally seen higher trap counts and earlier detections with the Scentry lures, suggesting they may be a bit more effective. A great comparison review of different lures and traps was recently published in the UMass Fruit Notes.

 

Onion thrips are just starting to show up in onions on our monitoring farms. Populations are still below threshold for now, but with hot weather on the horizon, outbreaks may not be far off. Thrips can be tricky to spot if you’re not familiar with them, but once you know what to look for, they’re pretty easy to identify. We’re mostly seeing yellow-orange juveniles (nymphs) tucked into the crevices at the base of onion plants. As they mature, you’ll start to notice the darker, blackish adults moving around.

 

In relation to onion thrips management, our team is currently testing a variety of tractor-applied mulches to evaluate their effectiveness in several ways, including their impact on thrips populations. We’re trialing two OMRI-approved paper mulches, black and silver plastic mulches, and a textured silver plastic. We’re also collecting data on soil temperature and moisture, pest management, and basic soil health indicators. Soon, we’ll be adding a prototype manure-based paper mulch made from upcycled manure solids. If any growers are interested in trialing some of the best-performing mulches next season, please reach out to our team. We’ll provide the mulch in exchange for your opinions and feedback on the mulch you’ve selected to compare to your “typical” practice.

 

Leek moth outbreaks are starting to show up in scapes on select farms in the region. The distribution appears to be patchy, as some farms are getting hammered while others remain mostly clear of leek moth. That said, we’re seeing a lot of pupae (cocoons) in garlic, suggesting that the next flight will likely begin soon. We expect to start seeing adults in traps next week. In terms of management and impact, it’s important to note that we haven’t observed yield losses in garlic or onions due to leek moth, even during severe outbreaks. Most marketable damage in these crops tends to occur during curing or storage, as larvae move down into the bulb away from the drying leaves. Topping garlic and onions before curing and storage can help reduce this risk. However, for leeks and shallots, we do see more direct impacts on yield. In those cases, exclusion netting or well-timed pesticide applications, typically about seven days after peak flight, can be effective. If you have any questions about leek moth, feel free to reach out. Our team has been researching these buggers for quite a while.

 

One pest that’s surprising us in the region this year is the presence of tortoise beetles in tomatoes across the Northeast. Although we’ve seen them sporadically on some farms in the past, they seem to be showing up more frequently this season. From what we’re hearing, they’re turning into a bit of a nuisance across the board.

We’re not sure what combination of factors has led to this unusual tortoise beetle year, but I wanted to share this in case you’ve been seeing them too. In our experience, they’re not typically a major problem and are hopefully just transient feeders on your plants. One cool thing to look for, if you are seeing them, is the larvae using their “fecal shield” to deter predators. The larvae actually hold their own dried feces over their backs like a little umbrella to ward off would-be attackers.

 

Other monitoring of note from the region:

 

• Swede midge damage from the first generation is showing up in brassicas in northern New York.
• Potato leafhoppers have been seen in NY and NH, which likely means they are on their way to VT or already here. We’ll report on them next week, but be on the lookout.
• Leafminer mines are being seen in beet, spinach, and chard in MA. We’re still seeing mostly eggs in VT at the moment.
• Cucumber beetles are in full force around New England.

 

Hi all,

Generally, around this time in season, we start to see the usual suspects showing up, and in some cases, thriving in the fields. This year seems to be a bit slower overall, but in warmer areas like the Burlington region, sightings are definitely picking up.

After a few weeks with relatively few Spinach/Beet leaf miners, we are now starting to see both eggs and mines in chard and beets. If you are scouting for leaf miners, start by checking the undersides of the leaves. Their small, bright white eggs are usually visible in tight clusters. Leaf mines begin as small, transparent tunnels in the leaf tissue and grow larger as the larvae develop. If you are already seeing mines in the foliage, be sure to remove the “infected” leaves from the field before the larvae exit to pupate. This will reduce the size of the second flight. If you have not yet seen any eggs or mines, but have in the past, it might be a good time to consider using insect exclusion netting or row cover.

Striped Cucumber Beetle (SCB) are also starting to appear in greater numbers. While we are still behind last year’s pace, beetle activity is definitely increasing. Keep in mind that SCB shows a strong preference for certain cucurbit species and cultivars. In general, C. maxima varieties such as blue hubbard and summer C. pepo types including zucchini and some summer squash tend to be more highly preferred than C. moschata varieties like butternut and winter C. pepo types such as acorn squash. Though feeding damage can be worrisome for smaller plants and seedlings, SCB are also a vector of bacterial wilt which can be quite a challenge. Our team is currently experimenting with a combination of trap cropping and baited bucket traps to manage SCB. We will keep you posted on how it goes.

Colorado Potato Beetle (CPB) adults are actively moving into fields, particularly onto eggplant and potato. So far, we are seeing mostly adults and very few egg masses, which indicates a slower start compared to previous years. One important note about CPB, based on our past work: in New England, CPB often prefers eggplant over most other solanaceous crops, or at the very least shows equal preference to potato. This can pose particular challenges for eggplant, as it tends to grow more slowly and is generally less resilient than potato. For growers with a significant investment in eggplant, prioritizing protection from CPB early in the season may be especially important.

Some other quick notes from around the area/region:

• The first leek moth flight seems to be over in the Champlain Valley. Most growers are beginning to larval feeding, particularly in garlic scapes.
• The first swede midge capture just across the river in Essex County, NY
• Three-lined potato beetle are out and about in Maine, probably here in VT too.

Finally, I want to acknowledge and extend heartfelt gratitude to our summer research scouts: Julian Wise, Emmy Juenger, Jill White, and Natalie Redfield Gale. These budding entomologists will be doing the bulk of the scouting work for the rest of the season. You may see them on a farm or at a farmers market. If you do, give them a high five! These scouting reports would not be possible without their tireless effort and sharp eyes.

A big shout out as well to Last Resort Farm, Khelcom Farm, and The Farm Upstream for generously allowing our team to scout and monitor on their land. Your collaboration makes this work both possible and useful.

You can now access our website via this link: https://go.uvm.edu/vpart. Also, you can now directly submit any pest sightings or questions to our team. Direct emails from the VVBGA listserve are acceptable as well. As always, you can access our pest reports on our website or by directly navigating to the scouting blog.

Feel free to reach out to us if you have any questions.

Cheers,

vic

Pest	Crop			Observations
Colorado Potato Beetle	Potatoes			We are seeing CPB adults and eggs in eggplant and potato. Populations are predominantly adults and eggs
Spinach/Beet leaf miner	Spinach, Swiss Chard, Beets			Adult flies are flying and laying eggs. We are seeing some mines in warmer areas
Striped Cucumber Beetle	Squash/Cucumber			Beetles are beginning to be seen in multiple areas
Flea Beetle	Broccoli/ Kale			Pressure seems relatively modest in most areas
Three-lined potato bug.		Tomatillos	They are being reported in Maine, likely are up and searching for tomatillos here in VT as well
Leek Moth		Onions/Garlic	We are seeing larval feeding, mostly in garlic scapes. Our traps are clear, so the first flight is over in the area.

 

Hi all,

The rainy and cool weather continues to dominate throughout the region and has shaped pest populations here in Vermont. Many pests are persisting that, in previous years, may have waned in their damage, while others seem to be arriving later than usual.

Some of the more persistent pests this season are the root maggots, particularly seed corn maggot, cabbage root maggot, and onion maggot. These pests are currently being reported and/or observed on various farms and seem to be causing significant damage. Seed corn maggot is the earliest to emerge in the season, while onion maggot is the latest (see degree day benchmarks below. According to degree-day models, onion maggot is currently at 50% peak emergence or less in Vermont. Fortunately, with the upcoming forecast of rising temperatures, we’re hopeful we’ll begin to transition out of this high-pressure period. Typically, warmer and drier soils reduce the viability of maggot eggs.

   Degree-Day Thresholds for Maggot Pests

Similar to the root maggots, slugs and isopods (a.k.a. rollie pollies) are also thriving in these cool, wet conditions. These non-insect pests require very high humidity to survive—which is nearly impossible to avoid right now. Sluggo is a highly effective organic option for slug control, and some growers report that it can help reduce isopod pressure as well.

We’ve received several questions about allium pests over the past week.

Allium Leaf Miner (ALM): This pest hasn’t historically been a major issue in Vermont, as it typically emerges in late April and enters its “summer hibernation” by early June. Since the fly spends most of the summer (June–September) in the soil as a pupa, it usually isn’t a major concern for onion growers. However, it can affect scallions or leeks later in the season. A telltale sign of ALM is a line of small white dots on the foliage.

Leek Moth: As mentioned last week, the leek moth flight appears to be ending, meaning most of the population is likely in the egg stage on alliums. We’ll be actively scouting garlic over the next couple of weeks for signs of caterpillar feeding and will report as soon as we see any. Typically, leek moth does not cause serious yield losses in onions or garlic, but it can be problematic if brought into storage on the foliage. Topping onions or garlic is a relatively effective, low-cost method to reduce their impact. Leeks, however, can be more significantly affected.

Finally, with potato planting season underway for many farmers, we wanted to share some recent research findings on Colorado potato beetle. In our delayed planting trials, we observed increased yields and reduced damage with plantings in late June to early July. The graph below shows results from a fully replicated trial at the UVM research farm. On-farm trials are currently underway, and we’re always looking for volunteers—or hearing from folks already trying some version of “delayed planting.”

Be on the lookout of the following pests:

Some pests that are being reported in more southernly and warmer regions are:

• Onion thrips are being found in MA, and a few farms in the warmer areas of VT
• Beet and Spinach Leaf miners are around in MA
• Cucumber beetles are in high tunnels and likely will be moving around quite a bit this week.

You can now access our website via this link: https://go.uvm.edu/vpart. Also, you can now directly submit any pest sightings or questions to our team. Direct emails from the VVBGA listserve are acceptable as well. As always, you can access our pest reports on our website or by directly navigating to the scouting blog.

Feel free to reach out to us if you have any questions.

vizzo@uvm.edu

Pest	Crop	Observations
Cabbage root maggot:	Brassicas	We are seeing damage in various early season brassicas including radishes. We are fully in the first generation of cabbage maggot.
Onion maggot.	Alliums	We have gotten reports that onion maggots are being found in some onion plantings in Chittenden Coutnty
Leek Moth	Onions/Garlic	First flight is waning, so much of the populations are likely in the egg stage.
Flea Beetle	Arugula, kale, broccoli	Beetles are being found in high numbers in many brassica crops. Row covers can be an effective strategy for protecting vulnerable brassica seedlings.
Cutworms:	Various crops	Cutworms are causing a lot of trouble in high tunnels and in the field. We’ve seen several large outbreaks in gardens around Burlington s

 

Hi all,

We’re back…

With UVM graduation behind us, our scouting and monitoring team is out setting up traps and scouting the crops that are out on our scouting farms. This season, we’re focusing on farms across three counties (Chittenden, Addison, and Washington) to give us a more representative sample of the region. This scouting and monitoring will again be supported by our soon arriving summer fellowship students. Without their support, we wouldn’t be able to provide these weekly reports.

Also, there are a few updates related to our webpage. First, we have officially dropped the E in VEPART, as we do more than entomology! You can now access our website via this link: https://go.uvm.edu/vpart. Also, in an attempt to improve communication with our team, we have added a couple of web forms on our webpage that will allow growers to directly submit any pest sightings or questions to our team. Direct emails from the VVBGA listserve are acceptable as well. As always, you can access our pest reports on our website or by directly navigating to the scouting blog.

Week in review

Ok, now on to the pests…Given the consistent cooler temps and wet conditions, our pest season has been relatively slow in comparison to last year. But some pests do tend to thrive in cooler spring conditions and their pressure can persist longer, as we are likely seeing this season.

Root maggots (e.g. cabbage maggot, seed corn maggot, etc.) are one of the suites of pests that do well under cooler conditions and seem to be thriving this spring. Once the overwintering generation emerges, these flies begin laying eggs at the base of their preferred crop hosts. According to NEWA’s degree day models,  overwintering populations (in most areas of the state) of cabbage maggot flies have reached roughly ~75-80% emergence in most areas of the state. Adult females are actively laying eggs at the base of brassica crops. With cool temps sticking around, this pressure is likely to continue. If possible, cover your smaller seedlings with row cover or insect exclusion netting, this can make a big difference in reducing impact.

Flea beetles: Flea beetles are making their way into brassica crops here in Burlington and across the southern part of the state. Similar to root maggot flies, row covers for small seedlings can be an effective strategy for reducing their impact on the sensitive plants.

 

Spinach/beet leafminer: We haven’t seen or heard of any outbreaks in Vermont yet, but reports of damage are coming in from the Hudson Valley. As with most leafminers, timely or pre-emptive action is key. Insect exclusion netting is a very effective method if applied before they arrive. The bright white leafminer eggs are relatively easy to spot on the undersides of spinach and chard leaves. Once the larvae get into the leaf they are very well protected from any control strategies. If you are seeing foliar damage, remove and destroy leaves showing active “mines” to reduce future pressure. Be sure to reduce any weeds, particularly lambsquarters, that might act as an alternative host for the pest.

Leek moth: Adults from the overwintering population are no longer showing up in most of our baited traps. Eggs are likely developing on alliums, but so far, we haven’t seen larvae or feeding damage in garlic or recently transplanted onions. Just a heads-up, leek moth larvae love garlic scapes. If scapes are important for your farm, be sure to keep an eye on these updates as we approach scaping season.

For detailed management information about these pests, as well as a comprehensive guide to current production and pest management techniques for commercial vegetable crops, check out the  New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions, using our new submission form and/or directly emailing me at vizzo@uvm.edu

Pest	Crop	Observations
Cabbage root maggot:	Brassicas	We are seeing damage in various early season brassicas including radishes.
Leek Moth	Onions/Garlic	Adult moths from the emerging overwintering population are no longer showing up in baited traps. Eggs are likely developing on alliums, however, we are yet to  see any larvae or feeding damage in any alliums.
Flea Beetle	Arugula, kale, broccoli	Beetles are being found in high numbers in many brassica crops. Row covers can be an effective strategy for protecting vulnerable brassica seedlings.
Spinach leaf miner	Spinach	Primarily being seen in tunnels in the Hudson Valley, though we presume that they will soon be active in fields in Vermont.

 

 

Hi all,

As harvest season ramps up, we’re observing a decrease in insect pressure on the primary crops we’ve been monitoring. However, there are some important signals to watch for in the coming weeks that could be crucial for managing potential pest outbreaks.

We found the first sign of Basil Downy Mildew on a susceptible variety of Genovese basil last week in Burlington. BDM can severely affect basil plantings and, if left untreated, can lead to complete crop loss. The telltale sign of BDM is a grayish color (from the developing spores) on the underside of basil leaves. It may sometimes appear as if soil has settled on the bottom of the leaf. If you suspect BDM, you can place the affected leaves in a Ziploc bag with a wet paper towel to encourage sporulation. Yellowing between the veins on the topside of leaves can also be an indicator of a potential outbreak.

A resource for identifying, reporting, and managing BDM is the Ag Pest Monitoring Site for basil. Though it seems from our checking on the site, that submissions for validated occurrences are not as consistent as in past years. Nonetheless, it is helpful to check if you are ever wondering. In recent years, some resistant cultivars have been developed. These cultivars and information on them may be found on the monitoring site too.

For those folks that have some later onion varieties in the ground or a good investment in leeks, we are seeing a high number of adult leek moths in our traps, suggesting that the latest flight is peaking.  If you are going to be harvesting over the next week or so, be aware that their may be some larvae or eggs in the leaves of your onions. We saw quite a few larvae feeding during our most recent onion harvest at the UVM research farm.   Topping is always a good option in that case. Not to mention, a significant amount of mildew and rot due to the consistent heavy rains this season.

Colorado potato beetle adults are emerging again and laying eggs on the undersides of potato plants. This new generation, combined with high pressure from early leafhoppers and increased precipitation, has severely affected many of the potato crops we’ve been monitoring. However, we are seeing some positive effects in our later plantings and research on delayed planting. While we haven’t analyzed the data yet, it appears that missing the emerging spring population of Colorado potato beetles might be a good strategy.

Updates from other nearby regions:

• Late blight found in Spartansburg, PA and Cattaraugus County, NY (8/13) and also in northern ME now, the same strains as the ones found in late blight infections in Ontario, Michigan, and New York this year.
• Corn earworm and fall armyworm now in Northern New York
• Alternaria leaf blight on cucumbers, watermelon, cantaloupe in Long Island

As always, our website for the scouting reports can be found here. In addition to the pests reported here, our website also has a more comprehensive list of pests. The list also documents the progression of many common pests as they emerge throughout the season.

For detailed management information about these pests, as well as a comprehensive guide to current  production and pest management techniques for commercial vegetable crops, check out the New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions.

Cheers,

VEPART Team

·      Pest	Crop	Observations
Colorado Potato Beetle	Potatoes, Solanums	Most populations are mixed stages, but adults have emerged for another generation and are laying eggs!
Squash Bug	Cucurbits	Adults and Nymphs are prevalent as normal for this time of year
Striped Cucumber Beetle	Squash, Cucumbers	Less bacterial wilt than previous yeasr
Flea Beetle	Kale, Collards, Cabbage	Not much of a problem at this stage, but we have an eye out for the latest brassica plantings.
Cabbage worms	Kale	Imported cabbage worm larvae are decimating some plantings and are especially prevalent in red Russian kale
Potato Leafhoppers	Potatoes, Beans	Leaf burn is extensive in various crops
Tarnished plant bug	Strawberries, potatoes	Tarnished plant bugs are being found in relatively high numbers in various crops. Some outbreaks in lettuce have been severe.
Leek Moth	Onions/Garlic	Latest flight is peaking and we are seeing larvae already in our harvested onions
Squash vine borer	Winter and Summer Squash	Pressure has been very high these days and this year!
Mexican Bean Beetle	Beans	Seeing larvae, adults and damage. Not extensive but some small outbreaks

 

 

Hi all,

Another week of hot and humid conditions has led to continued high pest pressure within the region. Not to mention that mosquito populations are at their peak of the season (we hope).  We are seeing most of the usual (insect) suspects these days, so it is more a game of managing impacts rather than avoiding establishment.

This season is shaping up to be one of the most severe for squash vine borers in recent memory, with multiple larvae often being found in single plants.  The situation has been further exacerbated by a seasonal surge in squash bug populations and some outbreaks of bacterial wilt, driven by cucumber beetles. Despite these significant pest pressures, the impact on yield has been relatively limited. Healthy cucumber and squash plants seem to be thriving in the current heat, which appears to be mitigating some of the damage.

Although cucurbits are facing significant insect pest pressure, we have not observed extensive disease issues on the farms we are currently monitoring. Some powdery mildew has been detected, but downy mildew has not yet appeared, although a recent confirmed case was reported in southeastern NY (Orange County). With the recent storms, we anticipate that downy mildew may potentially spread further north. Additionally, we have not yet encountered any basil downy mildew, though there have been confirmed reports in eastern Massachusetts.

Onion harvest has begun on many farms in the region, and it seems like a good time for harvest. Onion thrips were just peaking in the region and we’ve spotted some onion downy mildew. For those with onions still in the ground, be aware that leek moth populations in the Champlain valley are mostly in late stage larval and pupal stages. Which means that it is unlikely that you’ll be bringing in many eggs or early stage larvae into your storage or curing areas. Though, topping is always a good option to remove any doubt.

Some notes from nearby farming areas:

• Increasing western bean cutworm in Northern New York
• Lots of squash vine borer damage in Hudson Valley
• White rot confirmed in garlic in Maine

As always, our website for the scouting reports can be found here. In addition to the pests reported here, our website also has a more comprehensive list of pests. The list also documents the progression of many common pests as they emerge throughout the season.

For detailed management information about these pests, as well as a comprehensive guide to current  production and pest management techniques for commercial vegetable crops, check out the New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions.

Cheers,

VEPART Team

Pest	Crop	Observations
Colorado Potato Beetle	Potatoes, Solanums	Most populations are mixed stages, though we are seeing a lot of adults emerging these days
Squash Bug	Cucurbits	Adults and Nymphs are prevalent
Striped Cucumber Beetle	Squash, Cucumbers	Seeing the multiple incidence of bacterial wilt in the region.
Flea Beetle	Kale, Collards, Cabbage	Not much of a problem at this stage.
Cabbage worms	Kale	Imported cabbage worm larvae are decimating some plantings and are especially prevalent in red Russian kale
Potato Leafhoppers	Potatoes, Beans	Still seeing high pressure of adult leafhoppers in potato fields. Leaf burn is extensive in various crops
Tarnished plant bug	Strawberries, potatoes	Tarnished plant bugs are being found in relatively high numbers in various crops. Some outbreaks in lettuce have been severe.
Leek Moth	Onions/Garlic	Larval damage is extensive in all plantings.  We are seeing a lot of cocoons.
Squash vine borer	Winter and Summer Squash	Pressure has been very high these days.
Mexican Bean Beetle	Beans	Seeing larvae, adults and damage. Not extensive but some small outbreaks
Onion Thrips	Onions	Damage is becoming severe in plantings on black plastic.

 

Hi all,

First off, our team would like to express our support for the farming community during this challenging time. It’s disheartening to find ourselves conveying similar sentiments year after year, but here we are doing exactly that.  If there’s any way we can assist with your recovery efforts, please don’t hesitate to reach out. We have a dedicated team ready to lend a hand. Also, I want to acknowledge that due to some extenuating circumstances on our team, we were unable to get out the scouting reports the last couple of weeks, but we are now at full strength and out in the field again

With the consistent precipitation, we are seeing a lot of leaf diseases, which is no surprise. Some important updates regarding vegetable diseases in the region include:

Cucurbit downy mildew (CDM) has been reported in the Finger Lakes region and Hudson Valley of New York. While we haven’t detected it at our farms yet, given the recent storm systems, it may already be present in the region. This fungal-like organism does not overwinter here but arrives with storm fronts from the south. It often devastates late cucumber plantings in Vermont, appearing either later in the season or during active storm periods. CDM exclusively affects cucurbit plants, typically starting on older leaves and spreading to younger ones as the infection progresses. As symptoms worsen (via sporulation), the lower leaf surface develops a light grayish-purple “downy” appearance. Lesions can merge, leading to extensive tissue death and exposing fruit to sunscald. Severe infections can cause significant defoliation. Opting for resistant cultivars is the best defense, though conventional fungicides are effective. More information and images are available here: https://ag.umass.edu/vegetable/fact-sheets/cucurbits-downy-mildew

Basil Downy Mildew  (BDM) has been reported in Massachusetts. As a reminder, BDM is a pathogen that blows in from the south each year and once established in a field is very hard to manage. It really becomes a situation of damage control – getting rid of any diseased plants in the hopes of saving healthy plants. The reality is, once an outbreak takes hold, there is not much can be done other than the removal of diseased material. Also, a reminder that the Ag Pest Monitoring Site for basil is a great resource for identifying, reporting, and managing BDM.

Angular leaf spot in cucurbits is also being found in the region.  ALS is a bacterial disease that typically shows up earlier in the season because it is seedborne. Because of the many leaf spot diseases in cucurbits, it can sometimes be hard to diagnose even from visual inspections and photos. It is best to send in a sample to the plant diagnostic clinic if you want to be sure.

Some insect pest updates are:

Leek moth adults are still flying, but the trap numbers are declining. As this most recent flight wanes, we are seeing substantial damage in onion leaves and leeks. If you are beginning to see larval damage (i.e. window-paning on leaf tubes) in your onions, it is likely that the LM population has begun to transition out of the adult egg-laying phase. Window-paning in onions (from leek moth larvae) generally does not affect yield very much, marketable damage tends to occur in storage as larvae move into bulbs. We have found that topping onions in the event of a presumed outbreak can serve as an easy way keep larvae out of curing and storage areas.

Swede midge damage has picked up on many of the farms that we’ve been monitoring, especially in plants situated at the ends of beds. Red Russian kale and collards are consistently exhibiting the highest levels of swede midge damage. Though we have also seen some “blind heads” of broccoli, where swede midge larvae have fed extensively on the growing tip leading to the complete loss of a viable broccoli head.

It is shaping up to be an active year for spotted wing drosophila (SWD), especially in comparison to last year. The higher humidity and precipitation is providing ideal conditions for large outbreaks. We are finding SWD on all of the farms that we are monitoring and we are seeing some berries with SWD damage. Over the next couple of weeks we will be actively evaluating collected berries to determine actual pressure from larvae within berries.

We are also receiving a lot of emails from growers with reports of high numbers of Oriental, Japanese, and Asiatic beetles. Typically, scarab beetles are more of an issue in turfgrass and ornamentals, but sometimes can be an issue in herbs or waxy-leaf plants. Japanese beetles can be a bit of a pain in edamame too! Most issues from grubs of scarabs occur outside of veggie fields or fields that have recently been under grass cover crops or sod but big outbreaks in root crops can occur. There is limited evidence that entomopathogenic nematodes and/or fungi can be an effective control.

As always, our website for the scouting reports can be found here. In addition to the pests reported here, our website also has a more comprehensive list of pests. The list also documents the progression of many common pests as they emerge throughout the season.

For detailed management information about these pests, as well as a comprehensive guide to current  production and pest management techniques for commercial vegetable crops, check out the New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions.

Cheers,

VEPART Team

 

Pest	Crop	Observations
Colorado Potato Beetle	Potatoes, Solanums	Most populations are beginning to pupate in the soil, though we are seeing some 4th instars.
Squash Bug	Cucurbits	Adults and Nymphs are prevalent
Striped Cucumber Beetle	Squash, Cucumbers	Quite variable from plant to plant and farm to farm, but where there are outbreaks they seem to be rather concerning. Seeing the first incidence of bacterial wilt in the region.
Flea Beetle	Kale, Collards, Cabbage	Not much of a problem at this stage.
Cabbage worms	Kale	Seeing a lot of diamondback moth caterpillars and imported cabbage worm larvae.
Potato Leafhoppers	Potatoes, Beans	Still seeing high pressure of adult leafhoppers in potato fields. Leaf burn is extensive in various crops
Tarnished plant bug	Strawberries, potatoes	Tarnished plant bugs are being found in relatively high numbers in strawberries and potatoes
Leek Moth	Onions/Garlic	The second flight is waning and larval damage is extensive in all plantings.
Squash vine borer	Winter and Summer Squash	Seeing relatively high pressure in fields. Sometimes is hard to know if it is bacterial wilt or SVB
Mexican Bean Beetle	Beans	Seeing larvae, adults and damage. Not extensive but some small outbreaks
Onion Thrips	Onions	Damage is really starting to show in all of our onion plantings.