Hi all,
This week we are seeing some new insect pests that have begun to inflict damage around the state. Also, some of those pests that have been building in certain crops are now transitioning through their life stages and may be interacting differently with vulnerable crops.
The most important of the new findings for this week are:
- Leek moth are officially beginning their second “flight” of season. We are seeing modest numbers of adult moths in our baited traps. This is a clear indicator that adults are currently laying eggs on available alliums. In a week or two the LM caterpillars will begin feeding on the upper green leaves of plants. Their characteristic “window-paning” damage can be easily identified from a quick inspection. Onions tend to be relatively tolerant of LM feeding and can withstand quite a bit of damage before any yield loss is seen. However, bulb damage can sometimes occur during curing, as larvae or eggs may be brought into storage/curing areas after harvest. Topping of bulb alliums (e.g. onions, shallots, etc.) prior to curing has shown to be an effective strategy for preventing incidental larvae from contaminating storage areas.
- Mexican bean beetle adults are being found in bean crops within the region. We are mostly seeing adults mating and feeding within plantings. Some egg masses are being laid, but we haven’t witnessed any extensive larval feeding…yet. The bean beetle can be easily mistaken for the lady-bird beetle, as they are closely related. So be sure that you are correctly identifying them! If they get out of hand, they can be quite a pain. The parasitic wasp, Pediobius foveolatus, is a commercially available biological control that has shown to be a relatively effective if its release is correctly timed with the larval generation. You can find more information here.
- Colorado potato beetle populations are being found in high numbers in most solanum crops. Many of the now pinkish and plump larvae are just about ready to begin their journey down to the soil to pupate. Once they burrow into the soil within the field, they will spend 10-14 days before emerging as adults. Any control tactics implemented before the populations shift toward their pupation stage will greatly reduce the next generation of adults.
- As mentioned last week, Squash bugs are actively laying eggs all over summer and winter squash leaves. Though numbers seem to be down significantly from last year, there are still quite a few egg masses being laid in the crops that we’ve been scouting. Be on the lookout for their copper eggs on the underside of leaves. Row cover can also be useful prior to flowering There are some limited chemical options available for organic growers, and similar to striped cucumber beetle, squash bugs also prefer the maxima variety of winter squash.
Thanks to all of the growers that have reached out with there own questions and pest scouting information. All information and questions help us to better serve the needs of the VVBGA community.
| Pest | Crop | Observations |
| Colorado Potato Beetle | Potatoes | Most populations in the region are now a mix of large and small larvae. But there are many 4th instar larvae ready to pupate |
| Flea Beetle | Most all brassica crops | We continue to see flea beetle. However, because most brassicas are larger in size, the relative pressure from flea beetles is low. |
| Imported cabbage worms | Brassica crops (Kale, Broccoli, Cabbage, etc.) | Cabbage whites are flying and laying eggs. We are continuing to see larval feeding damage in many brassicas. Diamondback moth are also being found in brassicas in both adult and larval stages. |
| Leek moth | Garlic | The second flight of leek moth has begun! Adult moths are currentlty laying eggs in alliums |
| Mexican bean beetle | beans | Adults are being seen in significant numbers. Eggs and larvae are minimal at this point. |
| Potato Leafhoppers | beans and potatoes | Hopper burn is being found in beans and potatoes. It seems to be increasing in severity in many of the crops that we’ve scouted. |
| Striped Cucumber Beetle | Squash/Cucumber | Beetles are being seen and reported in numerous cucurbit crops. Numbers are becoming substantial and damage is significant, especially in cucumbers and C. maxima varieties of winter squash. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | Very few reports of leaf miner damage. |
| Squash bugs | Summer and Winter Squash | We’re seeing a plethora of adults and eggs with summer and winter squash. Nymphs are yet to be seen in any significant numbers |
| Squash vine borer | Winter squash | Moths are being found in traps from around the region. Moths are likely beginning to mate and lay eggs in squash plantings. |
| Tarnished plant bug | Strawberries | We are seeing a high incidence of tarnished plant bugs in the region, especially in strawberries. Cat-facing and other types of strawberry deformation from the “sting” of the bug has been seen. |