Hi all,
With the dry conditions persisting and new plantings sprouting across the region, we’re seeing a surge in pest activity on most farms. This is the time of year when vigilance in scouting is key to reducing pest pressure. We’ll keep you informed about the latest developments!
Some highlights from the past week at our locations are:
Several growers in Chittenden County, including here in Burlington, have reported Spinach leaf miner eggs and larval damage. Their small, bright white eggs are easily spotted on the underside of leaves. Spinach leaf miner infestations can worsen with the presence of lamb’s quarters and wild amaranth, which serve as alternative host plants. Effective weed management can significantly reduce their impact. For organic growers, it is recommended to use spinosad based products (i.e. Entrust) with an added spreader-sticker to increase the potential of contact or feeding from larvae after hatching. Of course, insect exclusion netting can also help if applied prior to their arrival. If you are not seeing eggs yet, it might be a good time to cover your chard and spinach!
Instances of three-lined potato beetles are increasing in many fields, particularly in Chittenden County. Despite their name, these pests seldom feed on potatoes, preferring tomatillos and ground cherries instead. They are often mistaken for striped cucumber beetles due to their similar striped pattern, but can be distinguished by their orange/red head and legs. Also, the yellow larvae of the three-line potato beetle feed upon the leaves of their host plant (and cover themselves in their own feces as a predator repellent!), in contrast to cucumber beetle whose larvae feed on plant roots. Exclusion netting or row cover can effectively protect susceptible crops from these beetles. Once an outbreak occurs, recovery without chemical controls becomes challenging.
As mentioned last week, Colorado potato beetle adults are actively mating and laying eggs on eggplants and early-season potatoes. Eggplants are particularly vulnerable during this period when potatoes are less prevalent. Keep an eye out for the characteristic orange egg masses under leaves, as larvae will soon emerge. Larvae are the most damaging stage of the beetle, but are also most susceptible to chemical treatments. Furthermore, research has shown that, for potatoes, the most important plant life stage for controlling CPB is during the flowering stage when tubers are beginning to form. Potato plants can tolerate quite a bit of foliar damage in the early and late stages of vegetative growth and still maintain yields.
Many of the root maggot pests, (e.g. seedcorn, cabbage, etc.), are actively feeding on plant roots in the soil. Growers in the lower Champlain Valley and warmer regions of the state are likely to see reduced pressure from many of these maggots as temperatures increase in those regions.
Be on the lookout of the following pests:
Some pests that are being reported in more southernly and warmer regions are:
- First swede midge trap catch of the season in Essex Co, NY last week.
- First cucumber beetles have been found in Northern New York. We are yet to find them in Burlington, but we’ll likely find them very soon.
- European Corn Borer has been found in traps in the Hudson Valley.
As always you can find our weekly reports at go.uvm.edu/pests
Feel free to reach out to us if you have any questions.
vizzo@uvm.edu & slewins@uvm.edu
| 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. |
| Spinach leaf miner | Spinach, Swiss Chard, Beets | Adult flies are flying and laying eggs. Some larval tunneling is being reported in NY and a few growers in Vermont. |
| Striped Cucumber Beetle | Squash/Cucumber | We have yet to find adults yet, but as cucurbits begin to be planted in the region, we imagine this will change soon. |
| Flea Beetle | Broccoli/ Kale | We are in peak flea beetle season. Large populations are being reported throughout the state. |
| Three-lined cucumber beetle | Tomatillos, ground cherries | We are seeing large outbreaks right now in the region |
| Cutworms | Various crops | Cutworms are causing a lot of trouble in high tunnels and in the field. We’ve seen several large outbreaks in gardens around Burlington s |