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
| Pest | Crop | Observations | ||
| Colorado Potato Beetle | Potatoes | All life stages are being seen on farms. | ||
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | No reported damage these days.. | ||
| Striped Cucumber Beetle | Squash/Cucumber | Beetle populations are really large on many farms. | ||
| Flea Beetle | Broccoli/ Kale | Very low | ||
| Three-lined potato bug. | Tomatillos | High pressure in most areas. | ||
| Mexican bean beetle | Beans | Still limited distribution. | ||
| Leek Moth | Onions/Garlic | Second flight is under way | ||
| Spotted Wing Drosophila | Berries | Still are yet to find any adults in our traps but there are traps just across the lake in Northern New York counties | ||
| Swede Midge | Brassicas | Still have not seen any damage, but there are positive identifications in traps in the region | ||
| Squash Vine Borer | Cucurbits | Adults being trapped in VT. Small numbers. | ||
| Squash Bug | Summer squash | Seeing nymphs, eggs, and adults. | ||
| Onion thrips | Onions | Low pressure thus far. | ||