Hi all,
What a difference a week makes. After the warm temperatures and dry conditions that ushered in the growing season, we are now experiencing much cooler, wetter and smokier conditions! Though the rains have provided us with much needed moisture, it comes with its own set of challenges, particularly related to pests and diseases.
One of the more important scouting notes this week is a prediction informed from the recent change in weather. The new storm systems arriving in the area are likely a precursor to potato leafhopper (PLH) pressure. Though we are yet to receive any reports of major outbreaks in Vermont, our hunch is that there are some small populations building in various crops. This is informed by our documentation of previous arrival dates and the recent storm activity. So, it is a good time to start scouting for the adults and small green nymphs. Tapping or brushing plants is one way to check crops for adults (they’ll jump/fly when disturbed) but you’ll need to look on the underside of leaves to find the wingless nymphs, which tend to be the most damaging life stage. The sooner you can identify them the better. Once you get “burned”, the damage is not reversible.
PLH can be a serious pest in a variety of crops including potato, beans, eggplant, alfalfa, strawberries, among many others. Legumes tend to be their preferred host. You will often see a spike in populations following hay-cuttings in the area. Luckily, PLHs are not able to overwinter this far north. However, once they are found in the region, they are here to stay for the season. PLH populations will exhibit explosive population dynamics, with rapidly growing populations soon after colonizing a crop, so be on the lookout and let us know if you see anything!
A few of the most important new developments:
Prior to the recent rains, we were finding onion thrips lurking in onion plantings at our monitoring sites, though they were yet to explode in numbers. Reports out of Massachusetts and New York corroborated our findings. Hopefully, with the new rains, these populations may be suppressed a bit. But that will be temporary! Also, there is some evidence that onion transplants being shipped into the region are harboring onion thrips. A word of caution: be careful when sourcing transplants from more southernly regions that experience pests earlier in the growing season. You may be jump-starting thrips infestations. Because thrips can reproduce asexually, it only takes a small population of thrips to start an outbreak.
Though the increased rains may suppress onion thrips they also invite slugs to the party. We have seen a spike in slug damage over the past couple of days as they move into the more hospitable (slug/snail) conditions. Slugs are particularly an issue in crops that capture and hold water within their foliage (e.g. napa cabbage, lettuces, etc.), though they can eat just about any broadleaf crop. Commercially available baits containing iron phosphate, are shown to be rather effective and with a low impact on the environment.
Spinach leaf miner eggs are hatching and actively tunneling into leaves. If you can get to those eggs it is always helpful to reduce the pressure, else removing leaves with mines and getting them out of the field can reduce the likelihood of second generation infestations.
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, and the rest of the VEPART Team and Collaborators
| Pest | Crop | Observations | ||
| Colorado Potato Beetle | Potatoes | We are seeing CPB in eggplant, but not in high numbers yet.
Mostly adults and a few egg masses. |
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| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | Adult flies are flying and laying eggs. Mines are beginning to be seen but less pressure than previous years at this time. Though we are seeing many eggs. | ||
| Striped Cucumber Beetle | Squash/Cucumber | Beetles are being seen and reported but populations are yet to spike. | ||
| Flea Beetle | Broccoli/ Kale | With the cooler temps and rains, we have seen less pressure than in previous weeks. | ||
| Imported cabbage worms | Brassica crops (Kale, Broccoli, Cabbage, etc.) | Cabbage whites are flying and laying eggs. We have not seen larvae yet, but that should only be a matter of time. | ||
| Tarnished plant bug | Strawberries | Tarnished plant bugs are being found in strawberries in the region. Cat-facing and other types of strawberry deformation from the “sting” of the bug has been seen. | ||
| Potato Leafhoppers | Alfalfa | There have been minimal reports of leaf hoppers, but be on the lookout | ||
| Three-lined potato bug. | Tomatillos | We are seeing some large outbreaks in tomatillos | ||
| Leek Moth | Onions/Garlic | We are primarily seeing pupae and late instar larvae. Though our traps are still clear, so the second flight is still yet to begin | ||