VEPART Pest and Scouting Report

Hi all,

With the middle of the season here and many people harvesting summer veggies, we’re also beginning to see some new stages of pests and the arrival of some diseases.

It is also that time of the year when you can take out that 80’s blacklight for the good of IPM! Yes, we are seeing outbreaks of tomato/tobacco hornworms throughout the region and several farmers are seeing some heavy pressure. One of the more fun ways to scout for hornworms, especially in high tunnels, is to bring out a black-light flashlight at night to spot the typically camouflaged pest on your plants. The cuticle of the hornworm will glow in response to the black-light and you can easily pick them off, as seen here. There are also some native natural enemies of hornworms, particularly the parasitoid wasp, Cotesia congregata, that can help to reduce their numbers. Being sure that there are small flowers consistently around to support the wasp population is a great way to keep the wasps active throughout the season. Research on floral resources has shown that buckwheat is a great choice for C. congregata (and for hover flies!). Wasps feeding on the nectar of buckwheat exhibit longer life spans!

Some other notable new pests and diseases:

Swede Midge seems to be a bit of a problem earlier this season than years past, particularly on the farms that we are scouting in Burlington. We were a bit surprised to find consistent and heavy pressure in cabbage, as it is typically not the most susceptible crop. Because the midge prefers to lay its eggs near the growing tip of brassicas, any of the “flower-head” brassicas (e.g. broccoli, cauliflower, etc.) are typically more vulnerable to larval feeding. Some recent UVM research has shown that even one larva can lead to marketable damage in these crops. As a result, prevention represents an important component of the IPM program for swede midge control. Insect exclusion netting can help to protect crops till flowers (broccoli, cauliflower), buds (Brussels sprouts), heads (cabbage) and/or stems (kohlrabi) can begin to develop.  Our research team is currently studying the variability of SM attractiveness in different kale varieties to explore the potential for the development of a trap crop system. You can see this research and more in our most recent research brief.

There have been several reports of Japanese beetle outbreaks on some vegetable farms. Though Japanese beetles are typically considered a pest of ornamental plants and turf grass, adults can certainly wreak havoc in some important veggie and fruit crops including basil, corn (silks), grapes, asparagus, etc. We’ve even seen some heavy pressure in solanums this year. For organic growers some possible options include neem and pyrethrin products. Also, some growers have sent us pictures of other scarab beetles (e.g. Asiatic beetle) on their farms. The control options tend to be similar for those beetles too.

We reported the presence of squash vine borer in nearby states a couple weeks ago, and now it seems that we are now seeing many SVB flying and laying eggs here in Vermont. As we previously mentioned, the primary sign of SVB is the wilting of squash plants and the presence of tunneling within the vines at the base of the plant. Unfortunately, once wilting is observed, there is very little that can be done to save the plant. Timely sprays or other applications based upon trap counts are a good protectant during flowering and one grower recently shared “as a last resort, [I] injected a mix of pyganic and organic spinosad into the holes where borers entered the crop. It worked and saved the crop. This is not preferable compared to timely sprays but something you can do if you miss spraying.”

Early blight is being reported in high tunnel tomatoes. Infections begin as small lesions, as they grow in size they exhibit a characteristic “bull’s eye” marking. Typically, early blight is sequestered and transmitted from infected plant refuse, solanaceous weeds, contaminated seeds or tubers. The fungal pathogen can then infect the leaves of new plants. Sanitation and rotation are key control tactics for reducing the likelihood of outbreaks.

Finally, we’d also like to acknowledge that all of the scouting, monitoring, data collection, and reporting behind these reports are the result of the hard work of our dedicated undergraduate research team – Gigi Walsh (UVM), Arianna Hee (UC Berkeley), Frieda Kahn (UVM), and Laurel Marshia (UVM).

As always you can find more details on other pests and diseases at our pest and scouting website.

Thanks always for your input and questions throughout the season!

Cheers,

The VEPART team

Pest	Crop	Observations
Colorado Potato Beetle	Potatoes	Currently most populations of CPB are dominated by older larvae which are about to pupate or are currently in the ground pupating. The second generation will be emerging in the next week or so.
Flea Beetle	Most all brassica crops	We continue to see flea beetle. However, because most brassicas are larger in size, the relative pressure from flea beetles is low.
Imported cabbage worms Diamondback moth	Brassica crops (Kale, Broccoli, Cabbage, etc.)	Cabbage whites are flying and laying eggs. We are seeing many larvae and some significant feeding damage in many brassicas. Diamondback moth are also being found in brassicas in both adult and larval stages.
Leek moth	Garlic	The second flight of leek moth has begun! Adult moths are currently laying eggs in alliums.
Mexican bean beetle	beans	Adults are being seen in significant numbers.  We are beginning to see more eggs and some larvae. We suspect that the upcoming week we will see more larvae and damage.
Japanese Beetle	Potatoes, Beans, Basil, etc.	There has been a marked increase in Japanese beetle populations in various crops. It seems like it might be a bad year for these pests.
Potato Leafhoppers	Beans and Potatoes	Hopper burn is being found in beans and potatoes. Though, most of the damage that we are seeing is being found in beans. Some of the pressure can be quite high.
Striped Cucumber Beetle	Squash/Cucumber	Beetles are being seen and reported in numerous cucurbit crops. Numbers are becoming substantial, and damage is significant, especially in cucumbers and C. maxima varieties of winter squash.
Spinach/Beet leaf miner	Spinach, Swiss Chard, Beets	A few growers have indicated that they are seeing increased damage from leaf miner. We haven’t seen much in our scouting that isn’t a remnant of the early outbreaks.
Squash bugs	Summer and Winter Squash	We’re seeing a plethora of adults and eggs with summer and winter squash. Most of the egg laying is being seen in summer squash. Nymphs are yet to be seen in any significant numbers.
Squash vine borer	Winter squash	Moths are being found in traps from around the region. We have seen many moths in traps and flying around summer squash plantings.
Swede Midge	Brassicas	We are seeing a lot of early season damage in brassicas. It seems to be earlier than past years to see the amount of damage that we are seeing.
Tarnished plant bug	Strawberries	We are stll seeing a high incidence of tarnished plant bugs  in the region, especially in strawberries and now raspberries too!