Hi all,
As plants in the field are growing to sizes large enough to tolerate high pest pressures, we are seeing some pest populations peaking within some crops. The larger plants combined with the wet weather is also a recipe for disease outbreaks over the coming weeks. We’ll surely be reporting on some of the more important diseases in the weeks to come. One particularly important disease that we touched upon last week is downy mildew (DM). Be sure to be on the lookout for DM, especially in cucurbits and basil. There have been reports out of Quebec with validated occurrences of DM in cucurbits, a lot closer that the New Jersey incidence reported last week. There are no reports of basil downy mildew (BDM) thus far, but if you see signs of BDM (e.g. gray/black spores on the underside of leaves, yellowing between veins on the upper-side of leaves, etc.) please contact the UVM Plant Diagnostic Clinic or email me directly.
Other key notes from the last week of scouting:
As mentioned last week, squash vine borer is actively flying in the region. We are finding relatively high numbers of adult moths in our traps, so be sure to check on those more susceptible varieties, especially C. maxima (e.g. hubbard) varieties.
We have officially deployed spotted wing drosophila (SWD) traps on several farms in Chittenden County. All of our traps have been clear of SWD adults, thus far. Our traps are situated in blueberry crops and will be continuously monitored through August. At the request of many growers, we will continue to report out each week in these “key notes” in addition to our website list. For those growers that would like to monitor SWD on their own farms, recent research out of UMass Extension has determined that a mixture of diluted grape juice (3 parts water: 1 part grape juice) with 2% (by weight) table salt, fermented for one week, is a cheap and effective bait mixture. You can hang a plastic container (4mm holes near the top) with some of the above concoction in your berry crop and check them weekly for easy monitoring. Also, we have a recently validated occurrence of blueberry maggot in Chittenden County. So, keep an eye out for larger maggots within blueberries, or if you have sticky cards out, look for the characteristic wing pattern for blueberry maggot (seen here).
Leek moth monitoring is mostly the same story this week. The second flight is still building, as we are seeing a slight increase in adult moths in our traps. However, the levels are well below the numbers we saw at this time the last few years. It seems that the second flight of adult moths may be a bit longer this year as cooler rainy temps have slowed down the moth’s development time. As it gets closer to harvest time for some alliums (e.g garlic), it is important to scout and see what stage (i.e. larvae, pupae, etc.) of moths you have in your crop. Unsuspectingly bringing eggs and/or larvae into curing and/or storage areas can be an issue. Our research has shown that topping alliums prior to curing can reduce the risk of damage from leek moth larvae occurring during storage and does not affect the long term quality of the crop.
Squash bug adults and eggs are being found in increasing numbers on all of the farms that we are monitoring. Check on the underside of leaves for their meticulously placed golden brown eggs. Straw or hay mulch can exacerbate squash bug outbreaks, as they tend to provide the perfect habitat for the pest during the hotter times of the day. The flip side is that straw mulch can reduce the incidence of squash viner borer. I guess it depends upon what you consider more of a threat. Like cucumber beetles and SVB, squash bugs tend to prefer maxima species of winter squash.
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, Ava, Katie, and the rest of the VEPART Team and Collaborators
| Pest | Crop | Observations |
| Spotted Wing Drosophila | Blueberries | Our monitoring traps are currently clear. |
| Colorado Potato Beetle | Potatoes | We are still primarily seeing adults and eggs, but presumably there is likely some growers that are seeing larvae…any day now. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | We are getting reports of a potential second generation of leaf miner occurring in Mass., but we are yet to see that occurring anywhere in Vermont |
| Mexican Bean Beetle | Beans | Oddly, the beans we were monitoring the last couple of weeks are now pretty much clear of bean beetle. We are unsure why, but that is the report nonetheless |
| Striped Cucumber Beetle | Squash/Cucumber | SCB is patchy across the farms we are monitoring. Some farms are having big outbreaks, while others are almost clear. Regardless, the population that are around are thriving. |
| Flea Beetle | Broccoli/ Kale | Flea beetle is mostly an after thought for the larger brassica crops, but second plantings may be effected as the cooler humid conditions are well-suited for flea beetle outbreaks. |
| Imported cabbage worms | Brassica crops | We are beginning to see damage in various brassica crops and reports of diamondback moth are coming out of Massachusetts |
| Tarnished plant bug | Strawberries | Tarnished plant bugs are being found in relatively high numbers in strawberries. |
| Potato Leafhoppers | Alfalfa | Fingers-crossed but leafhopper outbreaks have not been reported thus far. We’ll keep reporting. |
| Three-lined potato bug. | Tomatillos | We are seeing some large outbreaks in tomatillos and ground cherries. |
| Leek Moth | Onions/Garlic | The second flight is here and adults are flying but the trap numbers have been relatively low. The second flight may be extend this year. |
| Squash vine borer | Winter and Summer Squash | Trap numbers are increasing. Monitoring your squashes is advisable. |
| Squash Bug | Winter and Summer Squash | Populations of adults are peaking and eggs are being laid in high volumes. Few nymphs. |