Hi all,
We are entering peak harvest season for many crops in the region, and as a result some insect populations, despite their presence are becoming less of an issue. That said, as Ann Hazelrigg indicated in her recent post, disease incidence often increases as we get a bit later into the season and temperatures cool down and leaf wetness persists as evaporation slows on plants in the field. If you missed Ann’s post, you can search for her post via the listserv archive. That said, it is still important to monitor for some pests as there are some that can really be problematic later in the season.
One pest that begins to show signs of impact later in the season, and that we are seeing a bit of on farms right now, is the pepper maggot. This fly pest is related to several other agricultural pests, including apple maggot, blueberry maggot, and cherry husk fly. These flies can be easily spotted on yellow sticky cards, as they have ornate black striping on their wings. While it can be difficult to distinguish among these species, if you are seeing flies with black-striped wings around your pepper plants, it is likely that you have pepper maggot.
Pepper maggot flies typically begin emerging as adults in late July and lay eggs through most of August in the Northeast. Females lay their eggs on the sides of pepper fruit, leaving visible brown or black egg-laying scars. Once the maggots enter the pepper, they are well protected from most pest management tactics. This means that any insecticide application needs to be timed during the egg-laying period, before the maggots enter the fruit. For farms with a history of pepper maggot, monitoring with yellow sticky cards can help determine when flies are active and inform the timing of applications. There are also a couple of effective non-chemical options for reducing pepper maggot pressure, including crop rotation and trap cropping. Because the pest overwinters as pupae in the soil below its host plants, rotating peppers as far away as possible from previous infestations can be an effective strategy. For protecting sweet peppers, it is also well established that pepper maggot flies prefer to lay their eggs on spicy peppers, particularly hot cherry peppers, over bell peppers. In fact, it has been documented that a perimeter trap crop of hot cherry peppers can reduce pepper maggot pressure by up to 98% in interior bell pepper crops.
Another later-season pest that we are seeing in relatively high abundance right now is another fly, spotted wing drosophila (SWD). Our monitoring traps are beginning to show high numbers of male flies with their characteristic black spots on their wings. Females are much harder to monitor, as they do not have spots on their wings and require some form of magnification to identify their saw-like ovipositor, or egg-laying appendage. Importantly, males tend to show up later than females in traps. This means that by the time you are seeing males in your traps, there is a good chance that your fruit may already contain larvae. Including our own trap counts, we have received reports from quite a few growers that they are seeing signs of SWD in their later blueberry varieties, so we are really beginning to enter the high season for this pest.
Though insecticide applications can be relatively effective when properly timed, consistent harvesting to reduce the amount of time fruit spends in the field, followed by refrigeration, can also help reduce the impact of SWD on the saleability of fruit. Refrigeration can kill larvae that are already present in harvested fruit and is an important post-harvest management tool.
Some other notes from around the region:
- Corn earworm trap numbers high in the region
- Flea beetle beginning to pick up from the hot summer lull
- SWD (as mentioned above) is picking up all over the region
- Potato leaf hopper damage has really picked up as farms with infestations are seeing quite a bit of hopper burn.
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.
Finally, we would also like to acknowledge that funding for this year’s scouting program has been generously granted by VVBGA and the USDA Transition to Organic Partnership Program
Cheers,
vic
| Pest | Crop | Observations | ||
| Pepper maggot | Bell peppers | We are seeing some peppers with ovipositional scars, and some growers are reporting maggots in fruit | ||
| Potato Leafhoppers | Beans | Seeing mounting hopper burn where populations were high | ||
| Colorado Potato Beetle | Potatoes | Most potatoes are not seeing issues from the final generation | ||
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | Not seeing any | ||
| Striped Cucumber Beetle | Squash/Cucumber | Cucumber beetle pressure is not very high right now | ||
| Flea Beetle | Broccoli/ Kale | Pressure is certainly picking up in newly planted brassicas | ||
| Three-lined potato bug. | Tomatillos | Dwindling pressure | ||
| Mexican bean beetle | Beans | Still limited distribution. | ||
| Leek Moth | Onions/Garlic | Third flight is picking up, so egg laying is likely occuring | ||
| Spotted Wing Drosophila | Berries | We are moving into peak trap counts on many farms | ||
| Swede Midge | Brassicas | Seeing consistent damage on most farms, mostly in more susceptible varieties of brassicas (red Russian kale, sprouting broccoli, brussel sprouts. | ||
| Squash Vine Borer | Cucurbits | Still seeing consistently high numbers | ||
| Squash Bug | Summer squash | Consistent pressure, and now with the high number of adults we are seeing symptoms | ||
| Onion thrips | Onions | Damage is peaking but yields seem ok in most plantings. | ||