Hi all,
We are in the thick of the growing season, and so many plants have gotten to the point where they can tolerate quite a bit of insect pest pressure. Though, with the consistent precipitation, we are seeing a lot of leaf diseases. We also are expecting a change in weather with some cooler temps on the horizon. This may shift the distribution and types of pests/disease over the next week.
Leaf spot diseases are particularly prevalent right now in various crops. Alternaria is being seen quite extensively in melons and some other cucurbits in the region. A diagnostic characteristic of alternaria is brown lesions on the leaves that exhibit a “target-like” ring and a surrounding lighter halo. Alternaria inoculum primarily comes from infected plant material and can be viable for a couple of years in soil-bound debris. So, it is important to destroy or deep-plow any infested plant material and do your best to rotate out of cucurbits in previously infected fields for at least two year for large outbreaks. To reduce leaf wetness, it is also advisable to avoid overhead watering if possible. Obviously, with these rains, leaf wetness is a unavoidable condition.
Some other important updates are:
It is shaping up to be a bad year for spotted wing drosophila , especially in comparison to last year. The higher humidity and precipitation is providing ideal conditions for large outbreaks. As mentioned last week, we are trapping SWD on all of the farms that we are managing and we are seeing some berries with SWD damage. Over the next couple of weeks we will be actively evaluating collected berries to determine actual pressure from larvae within berries. We’ll keep you posted on those data.
We are also receiving a lot of emails from growers with reports of high numbers of Oriental, Japanese, and Asiatic beetles. It seems to be a higher volume of emails than in previous years. Typically, scarab beetles are more of an issue in turfgrass and ornamentals, but sometimes can be an issue in herbs or waxy-leaf plants. Japanese beetles can be a bit of a pain in edamame too! Most issues from grubs of scarabs occur outside of veggie fields or fields that have recently been under grass cover crops or sod. There is limited evidence that entomopathogenic nematodes and/or fungi can be an effective control. We are currently testing a couple of entomopathogenic fungi in potato fields with scarab beetle pressure. We’ll keep you posted.
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 | At our monitoring farm we are not seeing high levels of swede midge damage, but some recent farm visits have shown significant impacts. |
| Spotted Wing Drosophila | Blueberries | SWD is looking to be a significant |
| Colorado Potato Beetle | Potatoes | CPB populations are relatively manageable on the farms that we are monitoring. Most populations have adults emerging from pupation, and pressure is likely to build. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | The second generation of leaf miner is still increasing and we are seeing eggs in Vermont and other regions. Some leaf mines are being seen too. |
| Mexican Bean Beetle | Beans | MBB is continues to be relatively rare in the crops that we are monitoring! |
| Striped Cucumber Beetle | Squash/Cucumber | SCB populations have leveled out and pressure is less pronounced this last week. |
| Flea Beetle | Brassicas | Flea beetle pressure is returning, especially in recently planted brassicas. As the next week begins to cool a bit, we suspect that pressure from flea beetles will increase. |
| Imported cabbage worms | Brassica crops | ICW damage is extensive in almost all brassicas. |
| Tarnished plant bug | Potatoes and various other crops | Tarnished plant bug numbers were down this week |
| Potato Leafhoppers | potato and beans | Still no reports of PLH infestations |
| Leek Moth | Onions/Garlic | The second flight is over and larval damage can be quite extensive in some onion plantings. |
| Squash vine borer | Winter and Summer Squash | We are still seeing plants wilting from SVB in relatively high numbers |
| Squash Bug | Winter and Summer Squash | Squash bugs are high in most areas and continue to be an issue in susceptible crops. |