Hi all,
As we pass the halfway mark of August, many growers are already beginning to think about next year! For some, many of the pests that we’ve seen throughout the season have done their damage and are now just a part of this season’s history. That may be the case for most pests but there are still some pests that are rebounding and/or have grown large enough to cause greater damage.
In general, there aren’t many new pests to report on this week. Though, here are a few notes from the field this past week:
- We’ve been monitoring Basil Downy Mildew since reports of the disease popped up rather early in the season. It now seems that the disease is being found in and around Burlington and likely is prevalent in other areas. As a reminder, BDM is a pathogen that blows in from the south each year and once established in a field is very hard to manage. It really becomes a situation of damage control – getting rid of any diseased plants in the hopes of saving healthy plants. The reality is, once an outbreak takes hold, there is not much can be done. Also, a reminder that the Ag Pest Monitoring Site for basil is a great resource for identifying, reporting, and managing BDM. If you suspect that you are seeing BDM, please send us a message and/or send a sample to the Plant Diagnostic Clinic here at UVM.
- We continue to get reports of various Tomato leafspot diseases (Septoria and Alternaria) in the region. This is no surprise and is generally expected as the season marches into the later parts of the summer with higher humidity and summer rains. Cultural controls (e.g staking, drip irrigation, keeping up fertility , etc.) can be effective strategies and may minimize large outbreaks. The recent dry weather will slow the spread of the disease but with each rain, the fungus will move higher in the crop canopy. We’ve been lucky to avoid late blight, despite its arrival in Canada several weeks ago. There have been reports out of Maine regarding “air samples” of late blight spores, but no confirmed plant infections. So that is good news, all considering. We encourage growers to stay vigilant and report any potential late blight signs.
- Over the past week, we’ve gotten reports from several farmers that flea beetles are rebounding (in a major way) in many brassicas. Provided the dry and relatively mild summer temps (excluding a few days in early August), it is not a complete shock that we’re seeing larger than normal flea beetle pressure for this time of the year. Typically, flea beetle populations begin to wane during the hot and humid parts of the summer. Temps in the 90s, combined with humid/rainy conditions can suppress their populations. It may be counterintuitive that higher temps would slow insect populations, but it is important to note that insects have both a lower and upper threshold temperature range for development. Flea beetles typically do very well under hot (but not too hot) and dry conditions. This season, for much of the region, we have experienced the perfect storm for consistent flea beetle pressure. Insect exclusion netting is great for controlling flea beetles during the hotter times of the season, as it has less insulating capacity (i.e. R-value) than remay, but it may be fools gold for late season usage. Flea beetle larvae feed upon the roots of plants, and the netting may simply trap emerging adults.
- Swede midge populations seem to be building in many brassicas that we’ve been monitoring. Damage is being seen in a variety of brassica plantings and in some case it has been severe. Broccoli, cauliflower, kohlrabi, and collards are generally consider the most susceptible brassica crops and should be the most closely monitored. Be on the lookout for swede midge signs, like twisted leaves, scarring, and/or dead heads (not the tie-died kind).
Finally, reports from squash vine borer trapping programs in the region suggest that SVB population numbers are falling within the area and the risk from the pest is waning. We’re not out of the woods quite yet, but the falling numbers is a good sign.
As always you can find more details on other pests and diseases at our pest and scouting website.
Thanks to all of the growers that have reached out with their own questions and pest scouting information. All information and questions help us to better serve the needs of the VVBGA community.
Cheers,
The VEPART team
| Pest | Crop | Observations |
| Colorado Potato Beetle | Potatoes | CPB continues to be an issue in |
| Flea Beetle | Most all brassica crops | Flea beetle pressure is rebounding in a major way in many brassicas. |
| Imported cabbage worms | Brassica crops (Kale, Broccoli, Cabbage, etc.) | Cabbage moths are inflicting damage, but most of the damage seems to be tolerable. |
| Leek moth | Garlic | We are yet to see any new adults in traps. Last season we did see a third flight that affected leeks in some regions. We’ll keep monitoring to help predict if this will happen again. |
| Mexican bean beetle | beans | We’re seeing extensive damage in Burlington, but have not heard much from other regions. |
| Japanese Beetle | Potatoes, Beans, Basil, etc. | Generally, we’re seeing fewer scarab beetle issues in various plantings. |
| Potato Leafhoppers | Beans and Potatoes | Hopper burn is being found in beans and potatoes. Undeniably, beans are being the worst hit. |
| Striped Cucumber Beetle | Squash/Cucumber | Thus far, on farms that we are scouting, SCB populations seem to be more manageable this season. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | We are not seeing any expanding damage from leaf miners. |
| Squash bugs | Summer and Winter Squash | Squash bugs seem to be significantly down from last year’s seemingly record year. In general we have seen lower levels than years past. |
| Squash vine borer | Winter squash | Moths are being found in traps from around the region but they are falling. |
| Swede Midge | Brassicas | We are seeing increasing Swede midge damage in the most susceptible crops |
| Tarnished plant bug | Strawberries | We continue to see high pressure from TPB |