Hi all,
The last week of May is here, and as we move into June we are beginning to see some of our most common insect pests arriving in vegetable fields across the region. That said, pest pressure in many systems still appears to be somewhat behind where it has been in recent years. This is likely due, at least in part, to slower degree day accumulation compared to the same period over the last couple of seasons.
One pest that is just beginning to pick up speed in the area is the striped cucumber beetle. Several farms in the Champlain Valley are reporting beetles arriving in their fields, though populations are still relatively low as adults continue moving out of their overwintering sites. High tunnels are a bit of a different story, as our team has already observed some thriving populations within protected production systems. Many farms are using kaolin clay (Surround) applications to help reduce cucumber beetle feeding on recently transplanted seedlings. This can be a very effective strategy for helping young plants establish successfully. Kaolin clay combined with some form of exclusion netting can greatly improve early plant growth, allowing cucurbits to build enough healthy foliage to better withstand even relatively high beetle pressure with limited yield loss.
As mentioned last week, Colorado potato beetle is on the march looking for their favorite solanum hosts. This timing is a little behind previous seasons. For growers producing eggplant, it is important to be aware that CPB populations in this region are particularly attracted to eggplant. In fact, past research from our team found that Vermont CPB populations often prefer eggplant over potato. It is also important to recognize that resistance to chemical controls continues to increase across the Northeast for both conventional and organic management options. This has led to renewed interest in the development and adoption of non-chemical management strategies. Delayed planting has shown promise in some production systems, particularly on farms where limited land availability restricts the use of crop rotations at distances sufficient to reduce beetle dispersal and recolonization.
Keep an eye out for:
• Three-lined potato beetles are beginning to show up in ground cherries and tomatillos. Reports of their arrival have been coming in from Maine, and a couple of growers here in Vermont have also reported seeing a few adults milling around fields. Their name is a bit of a misnomer, as they are not commonly found feeding upon potato plants. They actually prefer other solanaceous species, particularly tomatillos. These buggers are often confused with striped cucumber beetles as their stripes are relatively similar. But if you take a close look you’ll see that the three-lined potato beetle has a distinctly orange/red head and is rarely found in cucurbit plantings.
• We are a bit surprised that we haven’t spotted any spinach leaf miner in spinach plantings so far. We have scouted several spinach and chard plantings, all of which have remained clean. This is encouraging news and may indicate that pressure will remain relatively low this season. However, it is still worth taking some time to inspect the undersides of leaves for their small, rice-shaped, bright white eggs. If action is taken once eggs are detected, most infestations can be kept at manageable levels.
• Slugs are also beginning to become an issue with the high humidity, cooler temps, and consistent rainfall over the past couple of weeks. We’ve seen damage building in some high tunnels.
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