Scott Lewins in a field

Welcome to the Vermont Entomology and Participatory Action Research Team (VEPART) Scouting report. Over the course of the growing season we will be reporting out on the major insect pests and diseases found at UVM’s Horticultural Research and Education Center. Reports can be found below.

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 and improved New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions. ( &

Pest and Disease Scouting Report (5/22/22)

Hi all,

With all of the heat and rain over the past week, several of our early season pests have begun to emerge and are being found in relative abundance in fields and high tunnels in the region.

As mentioned last week, we are particularly interested in keeping an eye out for signs of the allium leaf miner, (ALM), as we would like to monitor the expansion of this new invasive pest. The adult female fly deposits eggs directly in the leaves of allium plants leaving a distinct line of white dots (egg laying scars).  ALM’s impact is seen during the early spring and can be a significant issue for growers harvesting scallions or overwintered onions. The ALM displays a summer hibernation which typically begins around the first week of June and ends around September. So it typically is not an issue for garlic and onion growers. However, the second generation emerges just in time to affect any late season alliums (e.g. leeks). 

A few other highlights from the last week:

Colorado potato beetle: Reports of emerging adult beetles are being shared throughout the region. Adult beetles will seek out both wild and cultivated solanums during this time of the season. This overwintering generation will begin mating and laying eggs over the next week, so be sure to scout under the leaves of any solanum crops (e.g. tomatoes, eggplants, etc.) that you may have out there in your fields. 

Flea beetles: Flea beetles seem to be thriving, as we’ve seen some large outbreaks in brassica plantings. Row covers for small seedlings can be an effective strategy for dampening their impact on the sensitive plants. 

Cabbage root maggot: According to the degree day models from NEWA, overwintering populations of cabbage maggot flies are roughly ~95% emerged from their overwintering habitat. Adult females are actively laying eggs at the base of brassica crops. 

Striped cucumber beetle: Beetles have arrived on some farms, especially in unscreened high tunnels. We anticipate that these populations will be growing at a rapid rate over the next few weeks. 

Our new website for the scouting reports can be found here

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 and improved New England Vegetable Management Guide. And, as always feel free to reach out to us if you have any questions. &

Pest Crop Observations
Colorado Potato Beetle Potatoes CPB adults are currently emerging from their overwintering habitat,  these adults are searching out their first host plants to mate and lay eggs.  
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.
Striped Cucumber Beetle Squash/Cucumber Several farmers have reported the arrival of cucumber beetles in high tunnels
Flea Beetle Broccoli/ Kale Beetles are being found in high numbers in many brassica crops. Row covers can be an effective strategy for protecting vulnerable brassica seedlings. 

Scouting Report, 8/28/21

Hi all,

With many crops being removed from the field at UVM’s Catamount Farm and many other farms that we’ve visited, there has been a steep decline in documented pests/diseases.  However, there are some pests that are persisting in fall crops.

Some of the highlights are below:

  • There are growing reports of leek moth larvae being found on leeks within Vermont. Generally, the third flight of adults in August are the overwintering generation. These usually do not lay any eggs and head off to other areas to find a spot to be protected through the winter. However, when we have late season high temps, this can drive some of those adult moths to continue to mate and lay eggs on available alliums (i.e. leeks). This is what we presume is happening in the region, given the surge of warm temperatures this August. Any larvae that you are currently seeing are certainly the last generation. At this point, if you are seeing larvae, preventative measures are not effective.
  • Mexican bean beetle populations are still being seen in significant numbers in Chittenden County, VT. As mentioned last week, there is a  biological control (a paratsitoid wasp) that has shown some promise for controlling the beetle in the early stages of an infestation. You can find more information here: Mexican Bean Beetle Biological Control 
  • Swede midge damage continues to be a problem in late season brassicas. Some of the most susceptible crops from our scouting are collards, russian kale, brussels, and broccoli. Some smaller scale organic growers have reported success in reducing swede midge damage using insect exclusion netting. For broccoli, removing the netting after heads are formed seems to work well.
  • Late season berries are showing increased amounts of Spotted Wing Drosophila.
  • Corn earworm is being found in and around the region on many farms. Growers are reporting high numbers in Massachusetts and traps in the region are confirming large regional populations.
  • Though we have yet to see allium leaf miner in Vermont, it is known to occur in NY, Mass, and CT. The fall flight of adult flies generally occurs from mid-sept through October in the region. Be on the lookout for a line of white dots on the aboveground foliage of late season alliums.

As we have been consistently reporting, fungal leafspot diseases have taken their toll this season. Also, (Please click on any of the highlighted links for fact sheets related to the disease of interest)

  • Alternaria in brassicas; Alternaria and Septoria leafspot in tomato; Cercospora in beets, etc. Protectant fungicides applied weekly will help protect new tissue.
  • From regional extension networks, “Many poor looking tomatoes at this point: early blight, bacterial canker, septoria, nutrient deficiencies, hornworm defoliation, powdery mildew and leaf mold in tunnels, etc”
  • As reported last week, we are seeing downy mildews in young brassica seedlings. Downy mildew in cucurbits has not been diagnosed in the state  yet, but it is all around us.
  • Late blight has been found in potatoes in Maine and in Wisconsin but there is no imminent threat at this point. Choanephora rot is common on summer squash due to rains. Watch out for phytophthora fruit rot in pumpkins if soils are rain saturated for 24 hours.
Spotted Wing Drosophila Blueberries, Raspberries SWD larvae populations are being found in increasing numbers in late season berries. An easy way to test for SWD in your crops is to use the salt float method. Click here for instructions on the salt float method: Salt Float Test.
Colorado Potato Beetle Potatoes CPB is all but absent from most potato fields that we are monitoring. Most have moved to overwintering sites in the margins of fields.
Leek Moth Onions/Garlic Farmers are reporting leek moth larvae in leeks. See recent highlights above.
Striped Cucumber Beetle Squash/Cucumber We are still seeing the remnants of bacterial wilt in various squash and cucumber plots.
Squash Bug Squash Squash bug nymph infestations have really picked up due to egg masses beginning to hatch. Though most plants are tolerating the infestations.
Flea Beetle Broccoli/ Kale Flea beetle populations are rebounding and we are seeing increasing damage in late season brassica plantings. Damage in beets is also being reported on farms in the northeast.
Swede Midge Kale/Broccoli Swede midge damage continues to be found extensively in susceptible brassica crops and the highest pressure we’re seeing is in russian kale varieties, Brussels, and collards. A reminder that the tell-tale “blind heads” and scaring can generally be found at the center of the plant. Also, any strange growth like twisted leaves and stunted growth may also be a sign of infestations.
Imported Cabbage Worm, Diamondback Moth Broccoli and Kale Cabbage Whites continue to be seen flying around brassica plots. Brassicas are tolerating ICW damage. Diamondback moth chrysalises are being found frequently.
Squash Vine Borer Winter and summer Squash Squash vine borer has largely not been a problem on many of the farms that we’ve been visiting this summer.
Onion Thrips, Onion Downy Mildew Onions Thrips damage is extensive in onions across the region. Many farmers are reporting considerable amounts of onion thrips damage. However, with the harvest of most onions occurring in the region, control measures have largely been abandoned.
Tomato/Tobacco Hornworm Tomato We’re seeing more caterpillars arrive in tomato plots. The pressure, however, does not seem to be very significant.
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