Hi all,
With the consistent heat over the last few weeks were seeing some continued pressure from the usual (pest) suspects within the region. Luckily the dry conditions in much of the state has reduced the incidence of some of the more common diseases at this point in the season. The lack of moisture reduces the transmission and establishment of many diseases. For example, downy and powdery mildew in cucurbits seem to be mostly spotty within New England and we are not aware of any major outbreaks in Vermont.
Some notable pests and diseases from our monitoring this week:
We are hearing a lot from growers about their struggles with Colorado potato beetle. Yes indeed, it seems like a very bad year for folks with a significant amount of acreage in potato and other solanums, especially eggplant. According to some of our own research, CPB in Vermont actually shows a preference for eggplant. With the consistently high summer temperatures this season, we are seeing some extensive overlap in CPB generations leading to populations of mixed life stages (i.e. adults, larvae and eggs). Once a population becomes mixed with various generations, CPB control becomes rather problematic without some chemical intervention. In recent years, delayed planting has been as an emerging tactic for some growers in the region and is on our radar to explore more intentionally with research trials. Though it may not be helpful for this season, any growers interested in hosting delayed planting trials for CPB control (next season), please reach out. We are actively searching for farmers looking to adopt delayed planting or to establish best practices for the tactic. The more farms that participate, the easier it is to develop adaptable recommendations.
We reported last week that we have yet to see high pressure from spotted wing drosophila (SWD) this season. In fact, we were yet to find a single male fly in our traps. That luck is beginning to change as we are now seeing flies in our traps. Though the numbers are small at the moment, be aware that once you begin to find adult flies in traps, it is a good bet that your fruit has larvae feeding in them. We suspect that over the next few weeks SWD counts will be creeping up. This is bit later than last couple of years, so our hope is that this may lead to a lower peak population on some farms.
There has been a recent report of late blight symptoms on tomatoes in Canada within eastern Ontario. Despite this concerning news, the silver lining is that the outbreak is likely an isolated case and not an indication that the disease has arrived from a recent weather event. No other areas adjacent to the outbreak region have reported seeing any symptoms or validated cases. Despite this encouraging news, it is still important to monitor your tomatoes and potatoes for any sign of late blight. Common symptoms on tomatoes and potatoes are greenish-brown lesions on leaves and stems, that are often water-soaked and may be accompanied by white fuzzy fungal growth. It is especially important to monitor for potential infections after a heavy rain. If you suspect that you may have late blight, be sure to destroy any infected plants as soon as you are confident in your diagnosis. Late blight requires living plant material to survive, so destroying any living infected material will reduce the likelihood for spread to other areas on your farm or neighbors. We’ve been lucky to avoid any outbreaks over the last few years, but we still must be vigilant.
As always you can find more details on individual pests and diseases from our on-farm monitoring at our pest and scouting website.
| Pest | Crop | Observations |
| Colorado Potato Beetle | Potatoes | Pressure has increased in recent weeks with overlapping generations |
| Flea Beetle | Most all brassica crops | Flea beetles are rebounding and pressure is picking up and may effect newly planted brassicas |
| Imported cabbage worms | Brassica crops (Kale, Broccoli, Cabbage, etc.) | Cabbage worms in general are becoming problematic in several brassica crops, especially in high tunnels where parasitism and predation may be minimal. |
| Leek moth | Garlic | The second flight is over in the region. Larvae are feeding on onions and leeks. We are even beginning to see pupae in some alliums. |
| Japanese Beetle | Potatoes, Beans, Basil, etc. | In general, scarab beetles are a real problem right now. Japanese beetles, Asiatic Beetles, and Oriental beetles can all be a big problem for flower growers this time of year. We are even seeing high pressure in edamame plantings. |
| Potato Leafhoppers | Beans and Potatoes | We are seeing some high pressure in some areas, especially after cutting of alfalfa or other cover crops. |
| Striped Cucumber Beetle | Squash/Cucumber | SCB do not seem to be that bad this year. Despite some early season outbreaks, the SCB populations seem to be rather manageable. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | A few growers have indicated that they are seeing increased damage from leaf miner. We haven’t seen much in our scouting that isn’t a remnant of the early outbreaks. |
| Squash bugs | Summer and Winter Squash | We’re seeing a plethora of adults and eggs with summer and winter squash. Most of the egg laying is being seen in summer squash. Nymphs are yet to be seen in any significant numbers. |
| Squash vine borer | Winter squash | Vine borers are showing signs of picking up and |
| Swede Midge | Brassicas | Swede midge damage, though spotty on the farms we’ve been monitoring, where we are seeing it has been intense. If you have a history of swede midge be on the look out. |
| Tarnished plant bug | Flowers | TPB is becoming a real problem in some crops. They are especially showing high pressure in flower crops. |