Hi all,
As we begin the slow roll into June, it is peak season for the emergence and arrival of many of our most concerning insect pests. Unfortunately, it seems that the early season rains combined with warming drier temperatures, has led to some early outbreaks and arrivals.
One of the more important scouting notes this week is the arrival of potato leafhopper (PLH) populations within the northeast farming region. We have received warnings from both Maine and New York extension folks that PLHs are being seen in alfalfa and potentially other crops. 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.
We have not witnessed any hoppers or the characteristic “hopper burn” symptoms in any of the crops that we are monitoring, and we have yet to hear any reports of PLH from VT farmers. Though, it is only a matter of time before we see or hear about them in Vermont. So, it is a good time to start scouting for the adults and small green nymphs. Tapping or brushing the plants is one way to check plants for adults (they’ll jump/fly when disturbed) but you’ll need to look on the underside of leaves to find the wingless nymphs. The sooner you are able to identify them the better, as once you get “burned” the damage is not reversible.
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 often 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 other important notes from the past week:
As mentioned last week, Colorado potato beetle adults are actively laying eggs in eggplant and potato plantings. We’ve even seen some colonizing field tomatoes. In the next week or so, those eggs are will start to hatch, if they haven’t already. The larval stage of the beetle is the most damaging stage, so any control tactics should be timed accordingly.
We’re seeing a lot of slug pressure in lower lying wetter areas. Slugs are particularly an issue in crops that capture and hold water within their foliage (e.g. napa cabbage, lettuces, etc.), though they can just about eat any broadleaf crop. Commercially available baits containing iron phosphate, are shown to be rather effective and with a low impact on the environment.
Striped cucumber beetle are also actively colonizing squash plantings in the area. More and more growers are using floating row covers as an early season control strategy. Once plants are large enough and flowering, the row cover can be removed for pollination. Cucumber beetle are also vectors for bacterial wilt, so any efforts to reduce their populations or feeding early in the season is beneficial for the long-term health of the crop. Because they feed on a various weeds (e.g. wild amaranth, lambsquarters, etc.), it is important to be cognizant of the weed species in and around fields and manage accordingly.
| Pest | Crop | Observations |
| Colorado Potato Beetle | Potatoes | High numbers of CPB in eggplant and potato. Adults are mating and laying eggs at a precipitous rate. Eggs will be hatching soon if they haven’t already. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | Adult flies are flying and laying eggs. Many reports of leaf mining and eggs from various Vermont farmers. |
| Striped Cucumber Beetle | Squash/Cucumber | Beetles are being seen and reported in numerous cucurbit crops. Numbers are building in the field. |
| Flea Beetle | Broccoli/ Kale | We are in peak flea beetle season. Large populations are being reported throughout the state are continuing to be feeding and causing significant damage. |
| 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 | Reports of hoppers from NY growers indicate that hopper are being found in alfalfa. Maine has reported PLH in some crops too. They are likely here in VT, so be on the lookout. |