UConn Extension Vegetable IPM Pest Message & Reports from the Farm, Friday June 24th, 2016 [Comments or answers in brackets/color are provided by Jude Boucher, UConn Extension] Jamie Jones, Jones Family Farms, Shelton, CT We have most of our pumpkins planted. They are just coming up now. Only issue was in one field, the seeds were all eaten by turkeys. Some years they can be a real nemesis in some fields and return when replanted. Seems to be a bad year for us with turkey damage. Several fields need replanting. (Only lead seems to work). First plants have second true leaf showing. No sign of cucumber beetles yet We need rain. Interesting comment on pests, as insects haven t been much of a problem. One of our nagging problems in strawberries is the sap beetle - they never reached economic damaging levels this season for the first time in what seems like over a decade. Wish I knew why Jonathan Griffin, Oxen Hill Farm, W. Suffield, CT What a strange start to the season (although I feel like I m saying that EVERY year). Things are incredibly dry here, and hoping for a dose of rain this week to help out the unirrigated crops (potatoes, corn, beans). From a pest standpoint, it has been a pretty easy start. Earliest brassicas(mid-april) got hit by something as seedlings. I couldn't ID anything...but I had heard of other growers using BT to go after cutworms? Not sure We found significant CPB on our Asian eggplant (these were fields very close to young potatoes). Since the crew was going through and hand weeding the eggplant, we had them crush the adults and eggs. Surprisingly we have not seen them hit the potatoes left. This is good, as it can save my dollars and applications of Entrust. Striped cucumber beetle really knocked back early squash in one field. I sprayed with PyGanic, and they seem to be growing out of it. PLH are either here...or coming, so I'll be scouting more today. Rob Maddox, Sun One Organic Farm, Bethlehem, CT You wished some pictures? Attached are picture of our potatoes which look awesome and a picture of 25 CPB we pulled off after walking the entire field (about 1 acre)
Jude Boucher, UConn Extension Do your peppers look like this? Unknown pepper problem: upper leaves become distorted, twisted, torn, scorched. If so, I want to know. We have found five farms, scattered across the state, with large pepper fields (>1 acre on plastic) that have the same problem with top leaves twisted, torn, and scorched. Small plantings/farms don t seem to have the problem. It strikes the whole field at once across all pepper varieties or types. It doesn t strike the plants until they are about a foot tall and then the top leaves become distorted, as if they were being attacked by broad mites or a
massive thrips infestation but there are no thrips, mites, or aphids on the plants. They don t have bacterial leaf spot or canker or any fungal disease and it doesn t seem to be related to herbicide carry-over (different history in each field). We still need to check for viruses, but it doesn t look like any we have ever seen. Some growers grew their own transplants and some purchased them (we are going back to the sources to check for other customer complaints). The plants have been checked at two CT labs but we still have no probably cause, and they are not having this problem in any of the surrounding states. We re still working on it, but want to hear from you if your crop looks like this! We suspect that there are other fields out there where this is happening. We didn t find any ECB moths in the pheromone traps at the UConn Research Farm this week, so egg laying is over. We did find 2 squash vine borers in that pheromone trap. The threshold is to spray one week after you find 5 SVB moths in a trap. I m testing the furrow drench application of Coragen for SVB control to see if a single furrow application at planting can replace multiple applications later in the season. Farms that have high populations usually need 2-4 weekly applications with other broad-spectrum insecticides to control this pest. SVB moths Randy Rogowski, Laurel Glen Farm, Shelton, CT [reported by JB] Brassica crops 30% of the plants were infested with imported cabbageworm caterpillars. The threshold for conventional growers is 20% for heading Brassica crops and 10% for non-heading crops like kale and mustards. Also, 20% of Randy s plants had a yellow cross-stripped cabbageworm egg mass. ICW, diamondback moth and cabbage looper all lay their eggs singly, but cross-stripped cabbageworm moths deposit egg batches, so when they hatch you can have 10-20 caterpillars on a single plant, that can destroy that plant. The threshold to treat the whole
field for CSC is just 1-2% of the plants infested, or you can just spot spray individual plants that are infested (they are usually obvious due to extensive defoliation). Potatoes - Randy and his crew handpicked the few CPB that were found on his half-acre planting, even though he is not farming organically. Swiss chard was sprayed with spinosad for second generation leaf miners after we found egg batches last week. ICW larva on cabbage CSC egg mass Lars Demander, Clover Nook Farm, Bethany, CT [reported by JB] Onions no thrips on onions which are on silver mulch. I ll keep you posted on this because I m interested to see if this planting gets thrips. Tomatoes we scouted and did not find any early blight. He had sprayed the weeds between the plastic with Scythe (for broadleaf weeds) and Poast (for grasses) and got a good kill. The Scythe has an organic label and may offer good broadleaf control between plastic on organic farms. Brassica 40% of Lars plants were infested with ICW. We also found one CSC egg mass. He will spray with a synthetic pyrethroid (because he has it). Beets/Swiss Chard we found second generation leaf miner eggs, but he doesn t spray for this pest and only has light populations. Cucurbits no striped cucumber beetles present. Beans and potatoes we found up to 12 potato leaf hoppers per foot of row on beans and an average of 2-3 per plant on potatoes. Everybody should be scouting their beans and potatoes for leafhoppers now. The threshold for seedling beans is 2/foot of row and for larger beans (3 rd trifoliate leaf up until bud set) 5/ft of row. For potatoes, which are much more sensitive to hopper burn, just a single PLH per 50 leaves or about every two plants is enough to warrant a spray. Conventional growers should choose an insecticide with a longer residual period to help minimize how many times a planting needs to be sprayed, since the PLHs keep coming in on upper air currents. Below label rates of dimethoate will provide 10 days of protection. Neonicotinoids (group 4a) or synthetic pyrethroids (3a) will provide at least a week of protection.
Orthene will last for 10-14 days. Organic growers can either use pyrethrum (i.e. PyGanic) which only lasts for about 24 hours, or can spray to clean them up and then cover the plants with row covers to exclude the pests. Lars doesn t spray his beans he just harvests what they produce, but does want to protect his potatoes which have suffered heavy damage for leafhoppers in some years. Potato leafhopper on bean leaf Ben & Steve Berecz, The Farm, Woodbury, CT Pumpkins and winter squash we scouted many acres of these crops and didn t find a single cucumber beetle (amazing!), and the seed was not treated with insecticide. We did see small weeds breaking through their herbicides, due to the lack of moisture after application, and some fields required an immediate cultivation. In their winter squash field, the crows had hit the acorn squash seed harder than the rest of the squash and they will need to replant the acorn. If you can shoot and crucify a crow in the field, it will send a strong message to the others of the flock to stay away but it doesn t necessarily make you popular with your neighbors. Brassica 20% of the plants had ICW larvae. Time for a spray. Even low toxicity products such as B.t. work great on ICW. Tomatoes We scouted and found early blight lesions on the heirloom Brandywines. They will trellis the plants and then use Cabrio for the early blight. They plan to alternate with a Bravo type product on 7-14 day intervals (usually 10 days), depending upon how wet or dry the weather is. Beans they had 4 PLH/foot on seedling beans and will treat them to preserve their yields. Cole Van Seters, Freund s Farm Market, E. Canaan, CT Brassica 30% of their plants in their high tunnel (with sides rolled up) were infested with DBM and CL. Those were the first of those two pests that I have seen this year. DBM and CL are
more prone to resistance problems than ICW and CSC, so Cole needs to be sure to alternate between sprays so that the caterpillars don t learn to eat their insecticides. Squash and pumpkin fields we only found one plant with cucumber beetles and no treatment was needed. Cabbage looper larva diamondback moth larva Josh Bristol, Bristol s Farm Market, Canton, CT [reported by JB] Potatoes he had just sprayed earlier that day with Entrust for the CPB we found last week. We didn t find any PLH in their field after the Entrust spray. PLH is not mentioned on the Entrust label, but I have heard other organic growers mention that it seems to control them at least for a little while. Beans 2 PLH/foot of row on seedling beans and < 0.5/ft of row on flowering beans. He will treat his seedling beans with PyGanic. Sweet corn We scouted 50 plants per block in groups of 10 plants and found 8% of the pretassel stage planting infested and 4% of the late-whorl stage plants infested. Both blocks were under the thresholds of 15% for pre-tassel and 35% for whorl, so no treatment was needed. Brassica This was the only brassica planting scouted this week where we failed to find caterpillars. Time to scout your Brassica plantings. Onions - Josh also planted his onions on silver reflective mulch. We found an average of 1.5 thrips per plant down between the base of the leaves. The threshold is 3 per leaf. No treatment was needed. Collin Burson, Pinecroft Farms, Somers, CT [reported by JB] Sweet corn We set up our first corn earworm trap in his oldest sweet corn that is just starting to come into silk. The second and third plantings in the same field, now in the pre-tassel stage, that were free of borers last week now have 4% and 0% infested plants. His second field that had 10% and 0% last week, had pre-tassel plantings this week with 16%, 2% and 2%. Only the first planting with 16% requires treatment.
Eggplant we found plenty of CPB 1 st and 2 nd instar larvae and lots of eggs. He will treat with Coragen, Radiant or Agri-Mek. I ll just remind conventional growers that broad-spectrum insecticides such as synthetic pyrethroids can kill all beneficials and lead to aphid or mite outbreaks, and mites are a very common problem on eggplants. I ll also remind you that scientists have found a link between the use of some neonicotinoid (group 4a) insecticides and spider mite outbreaks on trees and some vegetables. Peppers we didn t find any ECB moths in the traps this week, which indicates that egg laying for the first generation is over and we shouldn t see much for borer increases in sweet corn until the second generation moth flight in late July or August. Tomatoes we scouted and failed to find any early blight lesions on the bottom leaves. We will scout again next week. Cucumbers we checked his seedling cucumbers and didn t find any cucumber beetles. Owen Jarmoc, CT Valley Growers, Enfield, CT [reported by JB] We scouted about 40 acres of cucurbit plants and didn t find a single cucumber beetle amazing who took them all. I m not complaining but it is really strange not to have June plantings infested with beetles, unless the seeds are treated, and these are not. That s all for this week. The next IPM pest message will be sent on Friday afternoon July 1st.