VPART Pest and Scouting Report

Hi all,

Not a ton of new pests to report this week. It’s very much more of the same, with several pest populations continuing to build around the region.

Onion thrips populations have been building over the past couple of weeks, and this past week we began to see some large outbreaks. Populations have surpassed economic thresholds in most plantings, likely due to the recent stretch of hot and dry weather. Thrips can be tricky to spot if you’re not, but once you know what to look for, they’re relatively easy to identify. Damage from onion thrips typically appears as silvery streaking on the leaves. While we do not typically see significant yield losses from thrips feeding alone, the damage can weaken plants and make them more susceptible to secondary diseases or other pests. Consistent rainfall can help reduce thrips populations, but if rains arrive after a thrips outbreak, the damaged foliage may be more vulnerable to disease development.

In recent years, many growers have begun using silver plastic mulch to discourage thrips establishment. Research does support its use, and our team is currently evaluating several tractor-applied mulches, including silver plastic, to better understand their effects on thrips populations and other crop pests. We are comparing two OMRI-approved paper mulches, black and silver plastic mulches, and an upcycled manure paper mulch that we have developed. This year, about 10 growers are participating in the project, and we are excited to get their feedback on these new mulch options. Hopefully, we will have some data to share with you all by the end of the season!

One final note on allium pests: we have received several questions about potential allium leafminer (ALM) damage in onions and garlic. Fortunately, we were able to rule out these suspected cases based on the pest’s seasonal biology. For those concerned about ALM in their summer onions or garlic, it is important to know that the insect is currently in a summer dormant period, which begins in June. During this time, the pest is inactive and adults will not emerge until the fall, so they are not causing damage in crops right now. It is also worth noting that we have yet to confirm a validated occurrence of allium leafminer in Vermont, so there is no evidence that the pest has become established in the state.

As mentioned last week, swede midge outbreaks are beginning to appear on several farms that we are monitoring. If you are in the process of planting fall brassicas, or planning to do so soon, it would be a good idea to scout any brassicas that are currently growing in your fields. If you are finding swede midge damage, deploying insect exclusion netting for your latest succession can go a long way toward reducing pressure on your fall crop.

Notes from around the region:

• Our spotted wing drosophila (SWD) traps are still clear on the farms that we are monitoring, but there have been positive trap catches across the lake in New York. Even there, however, numbers have been uncharacteristically low for this time of year.
• Squash bug populations are booming across the region.
• Fall armyworm and western bean cutworm have been captured in pheromone traps in neighboring states.

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Cheers,

vic

Hi all,

It looks like a very similar pattern to last year, with July bringing hot and dry conditions following a wet May and June. As we mentioned last week, this can be a mixed bag for pest and disease pressure. While hot and dry weather may slow the development of some diseases and insects, prolonged heat and drought can increase stress on crops. Extreme weather of any kind can also lead to unexpected or difficult to diagnose problems. Heat and drought stress can lead to symptoms that may mimic insect feeding or disease. That makes our job as scouts a bit more complicated, but we’ll still be out there each week doing our best to help identify issues and keep you informed.

After several weeks of encouraging growers to scout their beans and potatoes for potato leafhoppers (PLH), we saw several small outbreaks in beans on a couple of diversified vegetable farms this past week. This is a bit later than the past couple of years but falls in line with the general arrival time observed over the past decade. Although we are only seeing them in beans at the moment, potato leafhoppers have an extensive host range, feeding on more than 220 plant species, including both cultivated crops and non-cultivated or weedy species. The majority of these hosts (close to 62%) belong to the legume family, so perhaps they should really be called the bean leafhopper!

As mentioned previously, each spring potato leafhoppers migrate from their overwintering areas in the southeastern United States to northern regions of the U.S. and eastern Canada. Once they arrive and establish in bean and potato plantings, they typically complete two generations during the growing season. Interestingly, they begin preparing for their return migration rather early here in the Northeast. Previous studies have estimated that adult females begin preparing for their journey south as early as mid-August. At that point, female leafhoppers leave cultivated fields, stop laying eggs, and begin hitchhiking on favorable weather systems back to their overwintering regions in the Southeast.

While nonchemical controls for potato leafhoppers are most effective before they arrive and become established, growers with bean plantings that can be covered with insect exclusion netting may be able to delay or reduce infestations. Once a population is established in a crop, several conventional insecticides provide very effective control. For organic growers, field research suggests that pyrethrin- and neem-based products can reduce potato leafhopper pressure.

In addition to potato leafhopper, our team has uncovered several swede midge outbreaks in brassicas across the Champlain Valley and central Vermont, including Washington County. Swede midge is one of the more frustrating brassica pests, as it can decimate a crop if an outbreak coincides with the early stages of head formation in broccoli, cauliflower, and even Brussels sprouts. In recent years, we have noticed that many growers have begun planting sprouting broccoli as an alternative to heading broccoli. Unlike heading broccoli, swede midge damage to sprouting broccoli does not typically result in a complete loss of marketable yield, as the plants continue to produce side shoots and florets even after the growing tip has been damaged. This appears to be a good adaptation strategy, and we’ve heard positive things from several growers who have adopted this approach.

That said, anecdotally, we have been observing much higher levels of swede midge damage in sprouting broccoli plantings than in heading broccoli when scouting farms growing a diversity of brassica crops. Despite the increased damage, however, growers still seem to be harvesting respectable yields from these plantings. It makes us wonder whether sprouting broccoli could be functioning as a trap crop in these scenarios. It’s an intriguing possibility, and one we’d like to explore next season, if any farmers are interested?

Important notes from the region:

• Still are yet to see any spotted wing drosophila (SWD) on any of the farms that we monitor. We expect to see them soon.
• Sqaush bugs are beginning to pick up steam in summer squash plantings.
• Onion thrips are around but populations, in general have been spotty across fields. We’ll see if this pattern continues with the dry heat that is on the horizon.

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Cheers,

vic

Hi all,

This week’s scouting report is a bit later than usual after the holiday weekend, but we were able to get out and scout before the heat set in.

With the extreme temperatures, monitoring for insects can be both uncomfortable and somewhat futile, as insects, like us humans, are generally less active above certain temperatures. In fact, while we often think of insect development as being driven by temperatures rising above a lower developmental threshold, the opposite is also true for most insects. For the majority of insects in our region, temperatures above roughly 90°F will slow or even arrest development in much the same way that temperatures below their lower threshold do. Keep this in mind when thinking about how a heat wave affects insect populations.

As far as what we saw the past week, one insect that we are starting to see in our traps is the squash vine borer. Though we are seeing low counts in our traps, they have been caught which signals, that you should be considering the possibility of SVB in squash fields when you see a plant that wilts out of nowhere. The primary sign of SVB is the wilting of squash plants in the summer heat. With a closer inspection, you can find tunneling within the vines at the base of the plant. 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.

Exclusion netting can be useful for excluding moth from plantings, though this strategy is only useful prior to flowering and the need for pollinators. Well-timed applications, chemical and non-chemical (e.g. diatomaceous earth), near the base of plants during the early stages of flights can be useful. Traps with SVB lures can often provide growers with a good resource for timing controls for their specific farm.

Leek moth adults are starting to peak around the region, as we are seeing high counts in most traps.  Eggs are currently being laid on onions and other alliums, and we expect them to hatch within the next week, leading to larval feeding. Look for signs of leek moth caterpillar feeding, often recognized by “window-paning” in onion crops. For effective chemical controls, it’s best to apply treatments about 7 days after the peak, which should align near the end of this week for growers in the Champlain Valley.  It is also important to keep an eye on the stage of the leek moth population before harvesting garlic. If you cure or store garlic with the tops still attached, you don’t want to bring larvae or eggs into your curing or storage facilities. This is less of a concern if you are topping before curing or storage.

Important notes from the region:

• Spotted wing drosophila trap counts in New York are low but catches have occurred in Saratoga and Essex County. So far no SWD in our Vermont traps.
• Sqaush bugs are in all lifes stages (adults, eggs, nymphs) in squash plantings
• We are seeing limited onion thrips in onion but with the dry and high heat that is predicted over the next couple of weeks, we expect to see an increase in pressure.

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Hi all,

Some lovely weather over the past week, ended again with some heavy storms and rain here in the Champlain Valley and much of the upper half of the state. Given the consistent rains and cooler temps these weeks, we anticipate an increase in disease incidence, so it’s important to keep an eye out for any sick plants or signs of fungal diseases (e.g. mildews, etc.).

As mentioned last week,  potato leaf hoppers are likely on their way or may already be here. We have received reports of PLH in Massachusetts, and the recent storms originating from the south may have helped carry them into Vermont. Although our team has yet to detect PLH in any of the crops we are scouting, with reports so close to us, I imagine there are likely fields already harboring the pest.

Be aware that PLH can feed on a wide range of host plants, but they particularly favor legumes and potatoes. Because they have such a broad host range, they are often induced to move into crop fields during mowing. It is therefore especially important to scout beans and potatoes located near recently mowed fields.

The earlier you detect PLH, the easier it is to reduce their impact with insecticide applications if treatment becomes necessary. For smaller plots or garden beds, insect exclusion netting or other types of row cover can help protect young plants until flowering. For potatoes, there is some evidence that earlier season varieties tend to be more susceptible to PLH damage and associated yield losses than later season

Mexican bean beetle adults have been reported by farmers and gardeners at several locations near our scouting farms in Chittenden County. For folks with a large investment in bean crops, it is advisable to get out there and scout a bit. Once bean beetle larvae begin to pop out of their eggs, damage can build very quickly.  For growers utilizing IPM approaches, there is a rather effective biological control option available.The parasitoid wasp species, Pediobius foveolatus is commercially available within the region. The wasp is currently reared and sold by the New Jersey Dept of Agriculture and can be purchased from other biocontrol suppliers like arbico, IPM labs, etc.

Instances of three-lined potato beetles are increasing in many fields, particularly in Chittenden County. Despite their name, these pests rarely feed on potatoes, preferring tomatillos and ground cherries instead, with tomatillos being their favorite host.

They are often mistaken for striped cucumber beetles because of their similar striped pattern but can be distinguished by their orange-red head and legs. Another helpful way to tell them apart is by looking at the larvae. The yellow larvae of the three-lined potato beetle feed openly on the leaves of their host plants and famously cover themselves with their own feces as protection from predators. In contrast, striped cucumber beetle larvae feed below ground on plant roots, so if you see larvae feeding on leaves, they are not cucumber beetles.

Insect exclusion netting or row cover can effectively protect susceptible crops from three-lined potato beetles. Netting also allows plants to become well established before beetles arrive. In general, healthy, vigorous plants that are larger prior to infestation are much better able to tolerate feeding, and yield losses are often greatly reduced.

Quick notes from the field:

• Leek moth populations are beginning to start their second flight and are laying eggs.
• Caught our first squash viner borer in Burlington. More next week.
• Potato leaf hoppers have been seen in MA. Potentially are here in VT.
• European corn borer has been found in corn in Burlington. Check your plants for the characteristic line of “shot holes”

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Hi all,

With a long stretch of wet weather being predicted for the region, along with cooler conditions, disease incidence is likely to increase in many crops.   It is important to be pruning any diseased foliage and keeping airflow between plants and rows to reduce the likelihood of disease outbreaks.

Along with an increased probability of disease, storms originating from the south can also carry some unwanted pests up this way. One of the major pests that is transported up to Vermont each year are potato leaf hoppers. Although PLH is not hardy enough to overwinter here in Northern New England, PLHs hitchhike on the winds of storms to the region and quickly establish themselves for the season in alfalfa, beans, potatoes, strawberries, and various other crops. Our team is yet to detect PLH in any of the crops that we are scouting, but considering the frequency of storms and historical arrival dates, I would expect to see them very soon.

This is all to say that it is a good time to start scouting for the PLH adults and small green nymphs. Tapping or brushing plants is one way to check crops for adults (they’ll jump/fly when disturbed), but you’ll need to look on the underside of leaves to find the wingless nymphs. Because nymphs are often the most damaging life stage, early detection is critical. Once the characteristic “hopperburn” symptoms appear, the damage cannot be reversed. As soon as we begin finding PLH in our scouting network, we’ll be sure to let you all know.

The good news with the cooler temperatures and consistent rains is that many insect pest populations have been slower to build this season (e.g. onion thrips). This may allow for a bit of favorable asynchrony between pests and their crop hosts. With any luck, crops may be a bit more hardy and larger to provide some amount of tolerance in the face of pest feeding.

One pest that does not appear to have been slowed by the cooler weather is striped cucumber beetle (SCB). We continue to see high populations throughout the region and are receiving reports from growers struggling to keep adults in check. While both conventional and organic insecticides can provide effective control, cultural practices remain an important part of management. Exclusion netting, resistant or tolerant varieties, and physical feeding deterrents such as kaolin clay (e.g., Surround) can help suppress populations and reduce feeding injury prior to flowering.  Recent research on cucurbit susceptibility in the Northeast revealed the following ranking from most susceptible to least: bitter gourds, winter squash (C. maxima), cucumbers, summer squash, cantaloupe honeydew, butternut winter squash, watermelon.

Though cucurbit plants can often withstand a fair amount of foliar feeding by striped cucumber beetles (SCB), it is important to remember that these beetles are also vectors of bacterial wilt. In most cases, the transmission of bacterial wilt is a greater concern than the feeding damage itself, as infected plants can rapidly wilt and die.

Interestingly, though SCB are vectors of bacterial wilt, transmission of the bacterium does not typically occur directly from feeding and saliva deposition. In reality, the highest concentration and viability of bacterial wilt is found in the frass deposited by beetles as they feed.  Infection primarily occurs when frass comes into contact with feeding wounds on the plant. In theory, removing heavily damaged leaves and beetle frass may reduce opportunities for infection, although this is unlikely to be practical on a large scale. Rain might help!

Furthermore, bacterial wilt tends to wane later in the season. This may be because older cucurbit plants are less attractive to beetles, possibly due to changes in plant chemistry. Mature plants may also be better able to tolerate infection than young plants. As a result, bacterial wilt symptoms may develop more slowly or be less severe in older, larger plants.

In recent years, our team has evaluated a mass-trapping approach for managing striped cucumber beetles in squash production systems. While this strategy has shown promise in other regions, our trials have not yet produced consistent results. Maybe it is us! That said, we’d love to continue to refine the approach and would welcome opportunities to collaborate with growers interested in testing mass-trapping systems on their farms.

Quick notes from the field:

• Leek moth populations in the region are mostly in the cocoon stage, so a new flight will be on the horizon. Check your scapes, they love to feed on them
• First squash vine borer capture in NH, we are yet to see any in VT. More on this next week.
• CPB in VT are bad in most solanums, a bunch of growers are combining trap cropping with flaming + delayed planting.
• Low numbers of corn earworm and European corn borer picking up in MA, NH, PA

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Hi all,

I hope that folks are staying hydrated out in the fields as the unseasonably warm weather has

As mentioned last week, Colorado Potato Beetle (CPB) adults are moving around and we are now beginning to see both egg masses and small larvae. With the recent warm temperatures, these larvae are likely to feed aggressively and develop rapidly. For growers using insecticides, management is generally most effective when targeting smaller larvae, which are typically more susceptible to control measures than larger larvae or adults. It is also important to remember that CPB feeding has the greatest impact on yields when it occurs during flowering and early tuber bulking. Because flowering coincides with the onset of tuber development, protecting plants during this period can help minimize yield losses.

While CPB can affect potato growth throughout the season, the second generation often poses the greatest threat to yield. However, reducing populations early in the season can help suppress subsequent generations and lessen the risk of damaging outbreaks later in the summer.

Swede midge adults have been caught in traps throughout the region, and we assume that midges are now active in brassica fields. Recent research and farmer observations have highlighted some important host preferences for this pest. In most cases, swede midge outbreaks can significantly affect broccoli, collards, Red Russian kale, sprouting broccoli, and Brussels sprouts. Many curly kale varieties, heading cabbages, and Asian greens tend to be less preferred, although damage can still occur when populations are high.

For growers with large investments in brassica crops, insect exclusion netting remains the most effective non-chemical management option. Ideally, netting should be installed immediately after transplanting or seeding and remain in place throughout head development for heading crops. Once larvae enter the growing point, management options become extremely limited and head development is severely impacted.

Spotted wing drosophila has been trapped in Long Island NY and southern NY but we are yet to see any individuals in our traps in Chittenden. We’ll let you know as soon as we see SWD in our traps. For those looking to keep tabs on what is going on in nearby NY, you can always check Cornell Cooperatives Berry Pest Monitoring  Network.

If you are looking to set up SWD monitoring traps on your farm, there are two styles: baited sticky card traps and “drowning” traps. If you choose to use sticky card traps with lures, be sure to use red sticky cards, as they have been shown to be the most attractive. As far as drowning traps Scentry produces a commercial drowning trap or you can simply use diluted grape juice. Research out of UMass Extension has determined that a mixture of diluted grape juice (3 parts water: 1 part grape juice) with 2% (by weight) table salt, fermented for one week, is a cheap and effective bait mixture. You can hang a plastic container (4mm holes near the top) with some of the above concoction in your berry crop and check them weekly for easy monitoring.

Other sightings from around the region:

• Adult squash bugs are beginning to colonize cucurbits in the region.
• Leek moth second flight is yet to begin in VT
• Corn earworm has been caught in the region (MA, NY, NH)
• Cranberry fruitworm traps on a couple of farms are high

Finally, I want to acknowledge and extend gratitude to our newest summer research scouts, Eli Wilson, Darius Parker, Ava Kelly, Heather Boggis, Ella Venus, and Abbey Vranjes . These burgeoning entomologists will be doing a lot of the scouting work for the rest of the season.

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Hi all,

Generally, it looks like pest distributions are starting to align more closely with previous years as I look back at past seasons. We fell behind a bit with the cooler weather, but things have picked up recently.

Unfortunately, after several weeks of clean plants, we are now starting to see some Spinach/Beet leaf miner eggs in some select plantings in Vermont. No huge outbreaks yet but we now have confirmation that they are flying around in the region. If you have struggled with them in the past, you might want to consider covering any plants you want to protect. Scouting for leaf miners, is relatively straight forward. 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. The larvae feeding in those leaves will eventually make their way to the soil to pupate. Removal of those larvae from the field will reduce the size of the second flight.

Striped Cucumber Beetle (SCB) are also starting to appear in greater numbers. While we are still behind last year’s pace, beetle activity is increasing at a concerning pace in some of the fields we’ve scouted. 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.  If you are putting out any small starts, it might be helpful to employ some kaolin clay to slow the impact of their feeding.

Just prior to posting this report we received word from a local grower near UVM that Mexican bean beetle adults they are seeing a few Mexican bean beetle (MBB) adults in snap beans. This early alert should be helpful for those outside the warmer Burlington area. If you are in the Champlain Valley, it would be advisable to scout your crops over the next week for MBB eggs being laid on the undersides of leaves.

Once bean beetle larvae begin to pop out of their eggs, damage can build very quickly.  Luckily, for those growers interested in using biological control tactics, there is a rather effective option. The parasitoid wasp species, Pediobius foveolatus is commercially available within the region. The wasp is currently reared and sold by the New Jersey Dept of Agriculture and can be purchased from other biocontrol suppliers. For more information on the wasp and ordering directly from suppliers, you can check out the informative UMass website dedicated to the wasp.

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. There has been some discussion on the listserv and in other informal grower conversations about non-chemical options for CPB management. Thank you to everyone who has shared ideas with Stony Loam Farm about innovative tactics you are using on your farm, and thanks to  Dave Quickel for getting that conversation started.

Our team has been exploring CPB management strategies extensively over the past couple of years and is hoping to hold a field day or community meeting later this season to discuss shared challenges and successful approaches. If you are interested in joining one of these events, please reach out. We will share specific details as plans are finalized.

Some other quick notes from around the area/region:

• The first leek moth flight seems to be over in the Champlain Valley. You are likely to find most damage in the center of your garlic plants where scapes are beginning to form. You can squish them to reduce the population.
• The first swede midge capture just across the river in Essex County, NY!
• As mentioned last week, Three-lined potato beetle are out and about in just starting to pick up steam. Check your tomatillos if you got’m.
• We’ve seen some onion thrips outbreaks in high tunnels on over-wintered onions. That said, yields have not been particularly affected.

As always you can connect with us via our website: 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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Cheers,

vic

Hi all,

With the unseasonably warm temperatures over the last few days, pest development has surely advanced, and we suspect that many of the most common early summer pests will soon be moving into fields and high tunnels. Once these pests emerge, pressure tends to increase quickly irrespective of weather.

Pest Week in review

Flea Beetle: Flea beetles are thriving here in Burlington and reports from nearby regions suggest the same as it sounds like they are some large outbreaks in brassica plantings throughout the northeast. Row covers for small seedlings can be an effective strategy for dampening their impact on the sensitive plants.

Colorado potato beetle (CPB) adults are just starting to emerge from their overwintering sites and are just starting to be found in fields and gardens in the Champlain Valley. Today, while collecting wandering CPB adults searching for host plants in last year’s potato field, I was reminded of the importance of crop rotation for CPB management and the potential value of delayed potato planting as a strategy for reducing damage. As mentioned last year, our research team continues to work on a delayed potato planting project and is always interested in hearing from growers who have experience with this tactic, including any tips or approaches that have worked well on their farms.

Our team will also be sharing our experiences with CPB management at several summer and fall workshops and field days that will be announced through these reports, so stay tuned for additional information.These types of cultural controls are becoming increasingly important as reports of pesticide resistance, particularly to organically approved products such as spinosad, continue to become more common. In addition, some growers have developed innovative mechanical tools and implements for in season CPB removal, highlighting the growing interest in integrated and nonchemical management strategies.

A few other highlights from the past week:

Leek moth:  The first flight of leek moth is starting to wane in the warmer regions and we are beginning to see limited leek moth caterpillar feeding damage in garlic. Window paning damage are the primary symptoms that are most recognizable. Generally, economic damage in garlic tends to be limited to scapes, as the larvae tend to feed on the tops of plants. So, if garlic scapes are important for your farm, I would monitor any garlic plantings for leek moth damage to gauge their potential future impact on those scapes.  We expect the next adult flight to begin sometime in mid/late June.

Spinach/beet leafminer:  Though we haven’t seen or heard of any outbreaks in Vermont yet, looking at the degree day model for these leafminers, it seems that they should be flying around at the moment laying eggs on the underside of spinach and chard. 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.

Cucumber beetles have been spotted by several farmers in Chittenden County, though the sitings have been minimal, it is a good to know that they are moving around and soon to be in the field and potentially high tunnels in the near future! Be on the lookout.  I presume we’ll have more to share about them next week.

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.

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program

Hi all,

As we enter the second week of May and fields begin filling with transplants and direct-seeded crops, several insect pests are emerging from their overwintering sites and searching for suitable host plants.

You can 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.

Three of the most common maggots that we look for in the region are seedcorn maggot, onion maggot, and cabbage maggot. All of these pests emerge relatively early in comparison to other vegetable pests and are particularly troublesome as they can quickly damage young seedlings, roots, and developing stems before plants become established.  Monitoring and early intervention are therefore critical during this early spring period for susceptible vegetable crops.

While direct scouting for eggs or adults can be difficult for these pests, as they can be quite small. A useful tool for monitoring and predicting the risk level for spring maggots is the Network for Environment and Weather Applications (NEWA) IPM tools website. This site allows you to track the emergence of important pests and diseases using their respective degree-day development models. The number of models available for vegetable production is somewhat limited, but many important fruit pests are included.

According to the current models, we should be seeing adult flies laying eggs in much of the Champlain Valley, as the overwintering generation is between 50% and 100% peak emergence. Cooler central and northern areas have likely not yet seen much emergence, but with warmer temperatures on the horizon, it is important to consider the potential risk. The most important time to protect crops is during the peak emergence of the overwintering generation, especially when plants are small and vulnerable. Growers can target larvae with insecticide-treated seed or an insecticide drench, or prevent damage altogether by keeping egg-laying female flies off plants with row covers. Row covers need to be in place before adult flies begin emerging.

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.

In addition to maggots and flea beetles, leek moth adults are also currently flying, as adult moths are being found in relatively high numbers on both sides of Lake Champlain in baited traps. Generally the emerging generation of leek moth seems to inflict less damage than the second generation typically flying in mid-June. This is the result of a combination of few available cultivated hosts and smaller overwintering populations. That said, if you have overwintered onions or other alliums in an area where you’ve had leek moth pressure in previous years it might be useful to take some action to protect smaller plants.

As a reminder you can access our website via this link: https://go.uvm.edu/vpart. Also, there are a couple of web forms on our webpage that allow growers to directly submit any pest sightings or questions to our team. Direct emails from the VVBGA listserv are acceptable as well. As always, you can access our pest reports on our website or by directly navigating to the scouting blog.

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.

vizzo@uvm.edu

Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program