Hi all,
The past week of scouting and monitoring has revealed much of the same from the prior week. No new pests but increasing numbers and pressure from resident pests.
There have been several reports of fusarium in garlic. Fusarium can often be the result of a secondary infection from wounds being inflicted by other culprits such as mites or insects. So be on the lookout for signs of primary pests by checking any of the infected plants for potential initial sources of damage. This may give you some important information for managing the problem going forward.
Speaking of alliums, as garlic scapes are beginning to emerge in hardneck garlic, leek moth larvae are being found in modest numbers feeding upon or near those aromatic scapes. Leek moth larvae are known to preferentially feed upon garlic scapes and since populations are in the larval stage for most of the region, it is no surprise that we are seeing scape damage. If you value your scapes, it might be advisable to harvest them sooner than later. We anticipate that with warmer temperatures on the horizon, we’ll see extensive feeding and a fast transition from larvae to pupae in the next couple of weeks.
Some other important notes:
Cucumber beetle populations continue to build in the Vermont, especially in the warmer areas in southern VT and close to Lake Champlain. As mentioned last week, weed management and row cover can be effective strategies for reducing the impact on vulnerable transplants.
Colorado potato beetles are being seen in increasing numbers, but at our two monitoring sites we’re still only seeing adults and eggs. We presume that some of those eggs will soon be hatching and unleashing those voracious larvae. So be sure to be checking under leaves to see if eggs are beginning to hatch. The larval stage of the beetle is both the most damaging and susceptible stage of the beetle, especially for chemical control.
Spinach leaf miner damage is also being reported in much of the region. Damage can be quite severe in beets and chard. Once the larvae find their way into the leaf, control options can be limited. The characteristic small white eggs can be easily seen on the underside of leaves. There is some anecdotal evidence that the eggs are permeable to some chemical controls, but that remains untested. Preventive sprays before the eggs hatch can be useful if timed correctly. For organic growers, it is recommended to use spinosad based products (i.e. Entrust) with an added spreader-sticker to increase the potential of contact or feeding from larvae after hatching.
Finally, thank you to farmers that reached out regarding potential potato leafhopper sitings. As of now, we do not have a validated occurrence of PLH in Vermont. If you do think you are seeing PLH, please send along any pics or information you may have to Scott or me. We are in the process of setting up a submission form on our website for sharing details or questions like these, but in the meantime, just send any pest questions directly to our email addresses slewins@uvm.edu or vizzo@uvm.edu
| Pest | Crop | Observations |
| Colorado Potato Beetle | Potatoes | Still are not seeing any larvae but they are soon to be hatching. Be vigilant if you are planning any control measures. |
| Flea Beetle | Most all brassica crops | We continue to see large populations of flea beetle. We are especially seeing sustained populations in cooler regions of the state in the Connecticut River Valley. |
| Imported cabbage worms | Brassica crops (Kale, Broccoli, Cabbage, etc.) | Cabbage whites are flying and laying eggs. We still have not seen larvae yet, but that should only be a matter of time. |
| Leek moth | Garlic | Larvae are being found in modest numbers feeding on scapes in hard neck garlic. |
| Potato Leafhoppers | Alfalfa | Reports of hoppers from NY growers indicate that hopper are being found in alfalfa. Maine has reported PLH in some crops too. We are yet to see them or hear about them in VT. Be on the lookout. |
| Striped Cucumber Beetle | Squash/Cucumber | Beetles are being seen and reported in numerous cucurbit crops. Numbers are building in the field but the damage is not yet causing too much damage. |
| Spinach/Beet leaf miner | Spinach, Swiss Chard, Beets | We continue to see and hear of leaf mining and eggs from various Vermont farmers. |
| 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. |