Hi all,
Over the past two weeks with continued onslaught of rain and stormy conditions, it seems that disease and insect pressure is peaking in many crops. We are especially seeing a lot of disease in field solanums (e.g. potatoes, tomatoes, etc.) and cucurbits. This is no surprise with the high humidity and consistent leaf wetness.
In addition to disease buildup in potatoes, we are also seeing a significant rise in potato leafhopper (PLH) populations on our monitoring farms. Hopper burn combined with CPB feeding damage can significantly stress plants leading to potential outbreaks of leaf-spot diseases, blights, and other fungal pathogens. The fields that we are monitoring are exhibiting severe impacts from the insect and disease cocktail.
It has been a strange year for leek moth populations, as the second flight of leek moth adults extended through the entire month of July at low levels. This extended flight has led to a surprisingly large third flight, arriving right on the heels of the second flight. At the moment, our monitoring trap numbers are very high. We presume that adults are actively laying eggs on available allium foliage. The (poor) timing of the third flight may increase the risk of feeding damage occurring in onions currently being harvested and moved into curing/storage areas. As leaf tubes begin to dry down, newly hatched larvae tend to move closer to (or into) the bulb.
Topping onions prior to curing or storage can be an effective strategy for avoiding leek moth damage during curing/storage. The topic of onion topping has recently been explored on the VVBGA listserve. We would like to thank Stephen Chamberlain of Dutchess Farm for compiling feedback about the different approaches and outcomes from onion topping. It seems that the experience of most respondents supports our own research on the utility of onion topping as a leek moth avoidance strategy.
To reiterate for those who did not see some of the responses, here are a few select responses:
“We usually cut our onions at about the spot of the natural bend in the stem (2-3″ above the top of the onion) and also trim the roots. Then we just dry them in the barn in crates or boxes. They seem to last well into spring depending on the variety.”
“We fully clip all our onions leaving about a 2″ neck, in the field so we don’t spread leek moth from our off-site field to the home farm…They dry just fine for long-term storage, (until spring) so I imagine that short term storage would be fine.”
“I had good luck drying “Bridger” onions clipped. These were overwintered hoop house onions. The tops had fallen over and not yet dried. They stored excellently.”
Finally, we have begun to see high levels of spotted wing drosophila larvae in blueberries and raspberries. Recent berry sampling (i.e. salt floats) from farms in northwestern Vermont are exhibiting extensive outbreaks. Even berries that look healthy and taste great, are showing high levels of infestation.
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,
Vic, Scott, Ava, Katie, and the rest of the VEPART Team and Collaborators
| Pest | Crop | Observations |
| Swede midge | Brassicas | Really beginning to pick up, especially in collards, broccoli, and red russian kale |
| Spotted Wing Drosophila | Blueberries and Raspberries | SWD is being seen at its highest levels in several years in Vermont. |
| Colorado Potato Beetle | Potatoes | CPB populations are very spotty this year. On some farms we are seeing high pressure, while others seemed be relatively untouched. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | We are seeing some leaf damage in beets |
| Imported cabbage worms | Brassica crops | ICW damage is extensive in almost all brassicas. |
| Potato Leafhoppers | potato and beans | We are seeing major outbreaks in potatoes this past week. |
| Leek Moth | Onions/Garlic | LM adults are being seen in very high numbers in our traps. The third flight is looking like it will be a formidable population. |
| Squash vine borer | Winter and Summer Squash | We are seeing significantly fewer numbers of SVB |
| Squash Bug | Winter and Summer Squash | Squash bugs are high in most areas and continue to be an issue in susceptible crops. |