Hi all,
Our scout team was on a bit of a break last week, so this report is coming together with a bit of a gap from our last report.
With July upon us, the heat is welcome, but too much of a good thing can become a problem, and this heat is no exception. We’re seeing and hearing reports of significant heat stress symptoms in many crops, especially those grown in high tunnels or other protected systems. The combination of heat and humidity can also make it tricky to tell whether symptoms are due to disease or environmental (abiotic) stress.
One helpful strategy for telling the difference is to look at how the damage is distributed in the crop. If symptoms start in one area and spread outward, it’s likely a disease. If they’re evenly distributed across a section or the whole crop, an environmental factor is probably to blame. And if the damage appears randomly or in a more scattered pattern throughout the planting, it could be the work of a mobile pest like a flying insect.
As far as insects are concerned, we continue to see swede midge damage showing up on several farms. Most of the damage right now is in broccoli and Red Russian kale. The higher pressure in Red Russian isn’t a complete surprise, as our team has identified a particular preference by swede midge for this variety. If you’ve historically had issues with swede midge, it might be wise to steer clear of Red Russian kale.
If you’re planting a fall crop and are already seeing damage in your summer brassicas, you might want to consider using exclusion netting if that’s feasible for your scale. Also, keep in mind that midges can remain in the soil and emerge up to two years after an infestation, so plan your rotations accordingly if possible.
In addition, the Chen Lab at the University of Vermont is looking for growers dealing with swede midge to participate in a study exploring new nonchemical management strategies. If you’re interested, you can email our team directly and we will connect you!
Several growers have reached out to our team to inquire about the current status of Spotted Wing Drosophila (SWD) within Vermont. Our current SWD monitoring program across three counties has been quiet, as we have seen very limited numbers of SWD within our traps. With blueberry picking season beginning, we expect to see increasing SWD trap counts over the next couple of weeks. We will keep you posted on our traps. For those asking about which traps are best for monitoring, we’ve been having great success with the Scentry lures and traps. They seem to outperform most of the trap/lures that we’ve used over the years.
Regional Roundup:
- We have begun to see some Mexican bean beetle pressure on farms and that is a bit later than in previous seasons.
- Colorado potato beetle populations are mostly in their later stages and beginning to pupate in the soil. Folks planting late, may benefit by planting a crop asap, for seed potato at least
- Onion thrips are beginning to build, but the consistent rains have been a help on many farms.
- Diamondback moth is around and causing some damage on select farms.
- Western bean cutworm is being found in traps in NY and NH. Likely around in VT.
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, using our new submission form and/or directly emailing me at vizzo@uvm.edu
| Pest | Crop | Observations |
| Striped Cucumber Beetle | Squash, Cucumber | Beetles are beginning to be found in much larger quantities. Plants don’t seem to be particularly damaged. |
| Squash Bug | Squash | Mostly adults and eggs. |
| Colorado Potato Beetle | Potatoes, Eggplant | Seeing lots of larvae and high pressure in most potato plantings. Most larvae are in the last stages before pupating in the soil below plants |
| Flea Beetle | Potatoes, Eggplant | Low numbers of flea beetles but damage has been done in most crops. We’ll likely see a lull for the next few weeks as the temps pick up and first generations are pupating. |
| Leek Moth | Onions, Garlic | VERY high pressure in some plantings. Finding lots of adults in traps, so adults are laying eggs right now in the region. We estimate that we are just past peak in most areas of Vermont. Adult captures should be waning soon. Also it seems that the distribution of Leek moth is being found in new areas in the region, particularly NH. |
| Thrips | Onions | Thrips surprisingly are being found at lower numbers compared from previous years. |
| Cabbage worms | Kale | We are seeing some diamondback moth on some farms. Other cabbage moth caterpillars are present but not causing much damage. |
| Potato Leafhoppers | Potatoes, Beans | Some spotty distribution of adult leafhoppers in potato fields. Aren’t seeing any leaf burn. |
| Tarnished plant bug | Strawberries, potatoes | Tarnished plant bugs are starting to pick up in some crops |
| Mexican Bean Beetle | Beans | We are seeing bean beetle larvae in some plantings causing some extensive damage on some farms. |