Hi all,
As we move into the last week of July, many insect populations are entering their second generations, and pest damage in many maturing crops is beginning to show signs of a second round of feeding. Fortunately, many of these crops are at growth stages where they can better tolerate pest damage and weed competition. That said, direct damage during the later stages of crop development can still affect marketability.
One pest that is beginning to show the impact of its second generation is the leek moth. The majority of onion crops we have been monitoring are now showing signs of leek moth damage, and in some cases, we are seeing damage in upwards of 30–40% of onions within a field. However, much of this damage is not affecting yields, as the characteristic “window-paning” damage generally does not significantly reduce the amount of viable leaf tissue.
In addition, as many farms are harvesting garlic these days, be sure to inspect plants for signs of leek moth larvae crawling around on the tops prior to moving them into curing. Larvae can potentially move down toward the bulb to feed as the tops dry down, increasing the potential for bulb damage. Alternatively, topping garlic prior to curing and storage can remove any opportunity for leek moths to hitchhike into curing or storage areas. That said, topping is unnecessary if you do not see any signs of leek moth prior to harvest.
For those folks with berries, we have caught our first spotted wing drosophila (SWD) adult in our monitoring traps. Though this signals the beginning of the seasonal SWD infestation period, a single female out of nearly 20 traps on farms in the area is not a huge reason for concern. This is the latest that we have caught our first SWD in a trap in many years. This may be the result of a harsh winter knocking back populations in the fall, combined with the recent dry spell on many of the farms where we monitor. Regardless, this is a welcome result, as the smaller and slower SWD buildup may reduce pressure on this year’s blueberry harvest.
One pest that is causing significant damage on several farms right now is the imported cabbageworm (ICW), or cabbage white. Across many of the farms that we monitor, we are seeing high levels of ICW leaf damage, and in some cases, this has been severe, as we are seeing rather large caterpillars in most plantings. Monitoring directly for ICW caterpillars can be a bit difficult, as they are easily camouflaged by their green color on green brassicas. If you are looking for ICW caterpillars, be sure to carefully inspect the undersides of leaves, where they may be hiding, particularly the midrib of larger brassica leaves. For organic growers, Bt can be an effective chemical application, just be sure to get good coverage on leaves where caterpillars are feeding, as it needs to be ingested by the pest to be effective.
Notes from around the region:
- Squash vine borer peaking in most areas in the northeast
- Swede midge damage in brassica crops across the region
- Tarnished plant bug are thriving in many crops
- Fall armyworm, corn earworm, and European corn borer are all being found in traps in New York and NH, though the numbers are variable across the region.
- Onion thrips damage is high on many farms as the dry and hot weather continues.
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
Cheers,
vic
| Pest | Crop | Observations | ||
| Potato Leafhoppers | Beans | Higher pressure this week. Lots of nymphs and adults in beans, less pressure in potatoes at the moment. | ||
| Colorado Potato Beetle | Potatoes | Mostly late stage larvae and fewer adults | ||
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | Some signs of limited leaf damage beginning to mount these days | ||
| Striped Cucumber Beetle | Squash/Cucumber | Beetle populations are still really large on many farms. | ||
| Flea Beetle | Broccoli/ Kale | Very low and mostly inconsequential these days. | ||
| Three-lined potato bug. | Tomatillos | High pressure in most areas. | ||
| Mexican bean beetle | Beans | Still limited distribution. | ||
| Leek Moth | Onions/Garlic | Second flight is mostly over, but we are seeing high amounts of leaf damage as most populations are in their larval or pupal stage | ||
| Spotted Wing Drosophila | Berries | Caught our first adult in a trap this week. Only one so far. | ||
| Swede Midge | Brassicas | Seeing consistent damage on most farms, mostly in more susceptible varieties of brassicas (red Russian kale, sprouting broccoli, brussel sprouts. | ||
| Squash Vine Borer | Cucurbits | High trap numbers, populations are peaking | ||
| Squash Bug | Summer squash | Both adults and nymphs are starting to thrive | ||
| Onion thrips | Onions | High pressure in many onion crops at scouting sites. Seeing lots of damage these days | ||