VEPART Pest and Scouting Report

Hi all,

This week in addition to the typical cast of [inset pest] characters, we are starting to see an increase in disease incidence across the region. The distribution of disease has been variable throughout the state, owing to the scattered nature of rain and thunderstorms this season.

Thanks to Ann Hazelrigg of the UVM Plant Diagnostic Clinic, we have quite bit of important disease notes to consider:

• As has been communicated several weeks ago, Basil Downy Mildew seems to be rather prevalent in pockets within the state. This fungal-like pathogen blows in from the south and showed up earlier than usual this year. Top of the leaves look sunburned and undersides look dirty, as if dirt has kicked up from the ground. Resistant cultivars may get the disease later, but they are not immune. Be vigilant and promptly remove any plants that you suspect may have inoculant. 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.

 

• Tomato leafspot diseases (Septoria and Alternaria) are showing up on lower leaves of field tomatoes and outer rows in high tunnels. Cultural controls (e.g staking, drip irrigation, keeping up fertility , etc.) can be effective strategies and may minimize large outbreaks, but a few key fungicide sprays may be warranted mid season to ensure later crops. Dry weather will slow the spread of the disease but with every rain, the fungi will move higher in the plant.

 

• Though we are yet to hear of any confirmed incidence of cucurbit downy mildew in cucumber or melons within Vermont, it is just a matter of time, as it seems to be all around within the region (e.g. MA, NY, CT). This is a very early arrival for DM, in comparison to previous years.

In case you missed it, Meg McGrath of Cornell Cooperative Extension, shared the tips below for identifying CDM. Also, check out Meg’s link to biopesticide options here.

 

“Best time to scout crops for CDM is early morning (before 10).  Diagnostic is the grayish brown fuzz of the pathogen’s spores produced on the underside of the yellow, usually angular (on cucumber esp) leaf spots.  Spores are produced overnight when humid, especially when dewy, and then are released with humidity change in the am.  Growers who contacted me were looking at leaves in afternoon when the spores were gone.  When spores are not evident, put leaf upside down on damp paper towel in a closed plastic bag overnight.  If the spots are due to CDM, fuzz should be evident next morning. “

 

• There have been reports of bottom rot issues in lettuce due to wet conditions and poor air circulation. This is typically caused by rhizoctonia. Watch watering and weed pressure.

A couple important insect pest notes:

• With the recent hot dry spell, onion thrips have begun to take off on several of the farms that we have been monitoring. Typically, consistent rains help to wash the leaf tubes and knock back thrips populations. Overhead watering can mimic this effect and suppress thrips pressure. There is also some evidence that metallic mulch may delay or deter thrips from colonizing allium plantings.

 

• We are beginning to see the second flight of beet/spinach leaf miner within the region. This is a bit earlier from what we experienced the last couple of years. These leaf miners can cause significant marketable damage to chard, beet greens, and spinach. You can check crops for recent infestations, by looking on the undersides of leaves for their conspicuous white eggs. Weed control, especially for common SLM host plants like lamb’s quarter, can play a key role in reducing the likelihood of an outbreak.

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 there own questions and pest scouting information. All information and questions help us to better serve the needs of the VVBGA community.

Cheers,

Vic & Scott

Pest	Crop	Observations
Colorado Potato Beetle	Potatoes	In the upper Champlain Valley, CPB populations are transitioning to pupal stages. While in cooler regions of the state, CPB populations are largely in 3-4th instars, feeding away.
Flea Beetle	Most all brassica crops	Flea beetle pressure is largely a non-issue at this time of the season
Imported cabbage worms Diamondback moth	Brassica crops (Kale, Broccoli, Cabbage, etc.)	Status quo with cabbage moths/butterflies. We’re seeing feeding but outbreaks are mostly tolerable.
Leek moth	Garlic	Adult moths are currently laying eggs in alliums throughout the region.
Mexican bean beetle	beans	Adults are being seen in significant numbers.  We are beginning to see more eggs and some larvae. We suspect that the upcoming week we will see more larvae and damage.
Japanese Beetle	Potatoes, Beans, Basil, etc.	There has been a marked increase in Japanese beetle populations in various crops. Many farmers are reporting that this is a very intense year for JB.  It seems that, in general, we are seeing a lot of pressure from many related scarab beetles too (e.g. oriental beetle, Asiatic beetle, etc.)
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	The second flight of leaf miners has begun in the region. Be on the look out for their eggs on the underside of leaves.
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	Moths are being found in traps from around the region. We have seen many moths in traps and flying around summer squash plantings.
Swede Midge	Brassicas	We are seeing a lot of early season damage in brassicas. It seems to be earlier than past years to see the amount of damage that we are seeing. This seems to be a consistent trend this year.
Tarnished plant bug	Strawberries	We are seeing a high incidence of tarnished plant bugs in lots of crops this season. This week several farmers have expressed high pressure in fruit crops.