Hi all,
With the hottest days of the summer upon us and the plethora of maturing crops within the landscape, we are well positioned to identify the dominant trends for the rest of the season. You may often hear growers say that it is a “bad year” for a particular pest. These periodic outbreaks are typically the result of many factors that may be years in the making, or at the very least, a year in the making. This makes it difficult to predict an outbreak and sometimes hard to explain, even in hindsight. Some of the emerging “bad year” pests for 2022, include:, Japanese Beetle, Colorado Potato Beetle, Swede Midge, and onion thrips. Though the recent onion thrips outbreak around the state and region can be attributed to the hot/dry conditions that many growers are experiencing.
In honor of this unpredictability, we’d like to discuss a couple pests and diseases that have acted a bit unpredictable this season.
We’ve mentioned Basil Downy Mildew several times in the last few weeks, as the arrival of the disease within the region was quite a bit earlier this season and we were worried that it would cause early losses. However, despite its early arrival, BDM outbreaks have yet to be reported within Vermont. The limited spread of BDM is likely due to the hot and dry conditions over the past few weeks or perhaps a lack of reporting. That said, it is still important to stay vigilant and report any potential outbreaks.
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 within Chittenden County has been quiet, as we have seen very limited numbers of SWD within our traps. These numbers echo what several other extension professionals are seeing within other parts of New England. With blueberry season taking off, we expect to see increasing SWD trap counts over the next couple of weeks. We will keep you posted on our traps. For growers interested in trapping on their own farms, recent research from Jaime Piñero at UMass has shown that a simple diluted concord grape juice + salt mixture works better than many commercial traps. His research on comparisons of the traps can be found here. The basic bait cocktail is: 1 part concord grape juice + 3 parts water + 2% salt by weight.
Leek moth pressure has been very low in onion plantings on all of the farms that we have been monitoring this season. In reality, we have seen leek moth pressure fall, in onions, each year in Chittenden County since we began monitoring them in 2016. Despite trap counts being relatively stable over those years, we’ve documented less and less damage each year. This is a bit of a different story for leeks, as we have seen significant damage in leeks, especially late in the season, since the moth’s arrival in 2014. Currently, we are seeing the end of the second flight of adult leek moths in Burlington, as many of the populations have begun their transition to the larval stage. If your onions are currently under some type of exclusion netting, you’re probably safe to begin removing those over the next week.
As always you can find more details on other pests and diseases at our pest and scouting website.
| Pest | Crop | Observations |
| Colorado Potato Beetle | Potatoes | We are beginning to see the emergence of yet another generation of CPB adults. |
| Imported cabbage worms | Brassica crops (Kale, Broccoli, Cabbage, etc.) | Cabbage worm damage is really picking up. We are seeing quite a bit of damage in broccoli and kale. |
| Leek moth | Garlic | The second flight of leek moth is coming to an end, as we are seeing fewer and fewer adult moths in our traps. |
| Mexican bean beetle | beans | Larvae and damage is really picking up on some farms, while others are not having a problem at all |
| Japanese Beetle | Potatoes, Beans, Basil, etc. | There has been a marked increase in Japanese beetle populations in various crops. This seems to be a bad year for the beetle. |
| Potato Leafhoppers | Beans and Potatoes | Hopper burn is being found in beans, eggplants, and potatoes. Some of the pressure is increasing and showing significant damage. |
| Striped Cucumber Beetle | Squash/Cucumber | SCB is being found in high numbers, but the growth of the populations seem to be slower this year, when compared to years past. We are not seeing significant impacts on squash plants at the moment |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | The second flight of miners is well underway and we are seeing increased damage in beet greens and chard. |
| Squash bugs | Summer and Winter Squash | We’re beginning to see nymphs and increasing damage in summer and winter squash. |
| 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 and that is translating into high levels of damage on farms with a history of damage. |
| Tarnished plant bug | Strawberries | We are seeing a high incidence of tarnished plant bugs in the region, especially in strawberries. Cat-facing and other types of strawberry deformation from the “sting” of the bug has been seen. |