UConn Extension Vegetable IPM Pest Message & Reports from the Farm, Friday August 21th, 2015 [Comments or answers in brackets are provided by Jude Boucher, UConn Extension] We are currently under a late blight alert on tomato and potato and a downy mildew alert for basil and cucurbit crops. We have now found DM on all types of cucurbit crops: cucumbers, summer and winter squash, melons and pumpkins. I have heard back from growers who have treated DM on cucurbits, and Ranman, Tanos and Presidio all seem to be working on this strain, while Previcur Flex didn t seem to hold it in check. No feedback yet on other products. Steve Bengtson, Cold Spring Brook Farm, Berlin, CT CEW moths have dropped off to very low numbers again. Only one moth was caught in two traps over a 4 night period. This puts us at 0.125 moths per night which requires no spray. ECB counts were as follows: NY (E) = 2 up from 0 last week IA (Z) =0 down from 1 last week. Total of 2 up from 1 last week. Downy mildew found on basil in greenhouse in small amounts. We will try MilStop to control. Downy mildew has not shown up in our cucurbits so far the season and late blight has not shown up on our tomatoes to date. Phytoph thora is being held in check in our pepper crop thanks to the dry growing season. Heavy demand for all produce at this time on our stand. Fred Monahan, Stone Gardens Farm, Shelton, CT Sunscald on pepper, photo by Fred Monahan Sunscald seems to be the biggest problem on peppers right now. [Sunscald is a problem during periods of intense sunlight, especially for varieties with low foliar coverage or on plants that lodge or fall over during harvesting operations. Train your workers to hold the plant and twist the fruit off, rather than pulling the fruit off, to minimize how many plants get knocked over. You can also trellis the plants by running a line up both sides of the bed, using a stake every 10 plants or so.]
ECB=1/week CEW 1 field=.5/night [= 6-day schedule on fresh silking corn.] CEW by Housatonic River continues to be 0. [No spray needed in this field.] All of my young corn continues to be over threshold with FAW and ECB at tassel stage. Young Brassicas had flea beetle. Generic Warrior took care of them. Watering has taken up most of our time, we have pumped one pond dry, but two are full. Needless to say we need rain. I still have not added anything for late blight and see no sign of it so far. We have seeded the last dill and cilantro in the herb garden which should get us through till frost. I have one more set of basil transplants to set out next week and continue to alternate between Ranman and Quadris. Steve and Ben Berezc, The Farm, Woodbury, CT [reported by JB] Sweet corn: zero corn earworm in pheromone traps. They are not spraying silking corn at this time. Eggplant: They sprayed with Warrior to kill the leafhopper nymphs which caused the leaves to curl (reported last week). This week we scouted for mites because broad-spectrum insecticides like synthetic pyrethroids kill most of the beneficials in a crop, and in the case of eggplant, often cause mite outbreaks. Unfortunately there are few selective insecticide options for this crop. When scouting for mites, look for white stippling on the leaves and webbing on the underside of the leaves near large veins. No mites found this week. Tomatoes: the biggest problem on most farms right now is that the heavy fruit load, aided by high winds, are causing the stakes to break at ground level and the trellis systems to topple over. This exposes fruit to sunscald. Tomato stakes should be spaced every two or three plants to minimize this problem. Broken tomato stakes
Josh Vincent, Vincent Farms, W. Suffield, CT [reported by JB] Sweet corn: 0.25 CEW moths per night = 6-day schedule on fresh silking corn. ECB: Only 3 moths were captured in traps this week, down from 12 last week. Peppers: Josh applied a spray for borers (one week after capturing at least 7 moths in his traps). Cucumbers: Only a couple of leaves midway between spray allies showed any sign of downy mildew. His last spray was with Presidio and it seemed to hold off the disease quite well. Pumpkins and winter squash: Josh applied his third fungicide application of the season this week and used Quintec for powdery mildew, Bravo for the fruit rots like black rot and Plectosporium, and Forum for downy mildew. His prior applications for powdery mildew were with Vivando and Torino, and for downy mildew either Ranman or Presidio. Willy Dellacamra, Cecarelli Farm, Northford, CT [reported by JB] Sweet corn: They captured an average of 2 CEW moths per night and are on a 4-day spray schedule on fresh silking corn. It is not uncommon for farms near the coast and along the CT River to get higher numbers of moths before inland farms, as the moths use the winds along the coast to migrate North. Peppers: Only 2 ECB moths were captured this week, down from 3 last week. Peppers still do not require an insecticide for borer and are being harvested worm-free. Lunchbox sized peppers had bacterial leaf spot on the plants from the start, which severely damaged the plants and has prevented them from setting fruit. Copper applications have helped prevent the spread to the larger sweet peppers. Jonathan Griffin, Oxen Hill Farm, Suffield, CT [reported by JB] Corn: We set a CEW pheromone trap in his first silking corn of the year. Pre-tassel stage corn had less than 1% of the plants infested with FAW. Broccoli: We found all four caterpillar species in his planting: imported cabbageworm, diamondback moth larvae, cabbage looper and cross-stripped cabbageworm. 70% of the plants were infested and the threshold is 20%, so he sprayed this week with Entrust. It is important for growers to scout for caterpillars during heading and to treat if they exceed thresholds to avoid shipping worms between the florets of the head. Brussel sprouts: We are starting to find cabbage aphids and Alternaria leaf spot. Spray when 10% of the plants have cabbage aphids. Aphids distort leaves which curl around the aphids and protect their colonies from sprays and natural enemies. Organic growers can use insecticidal soap, neem-type products, PyGanic with a surfactant, or Mycotrol-O, and MA growers have found that combinations of these products work for heavy infestations. Aphid infestations usually start at the top of the plants, so topping plants early to help size upper sprouts and prepare for harvest, can help remove colonies before they really get going and improve the results of insecticide applications. Alternaria usually arrives in the seed, so hot water seed treatment and resistant varieties should be used. Also, clean up early plantings after harvest so
that the amount of disease on the farm is limited and not allowed to snowball as the season progresses. Cabbage aphids on Brussel sprouts. Cucurbit crops: we are finding both powdery and downy mildew. He will treat with sulfur and copper or Oxidate and then copper. Peppers: We opened fruit at his Granby pepper field and confirmed that about 30% of the fruit were infested with pepper maggots. Most, but not all, of the maggots had emerged from the peppers and gone to ground to pupate in the soil. Pepper maggots seem to be a real threat in the Suffield and Granby areas. Next season Seduce or GF-120 Fruit Fly Bait applications will begin as soon as the first stings or flies are detected or trapped. Damaged fruit that has turned red will be removed from the plants/field this week and destroyed. Peppers will be rotated to another field in Suffield next season. Conventional growers can use dimethoate or Orthene after the stings or flies are detected in July to prevent damage. It is suggested to plant a cherry pepper plant in the outer row of pepper blocks every 25-50 feet to help monitor for stings on the glossy fruit during July. Potatoes: Tubers have reached good marketable size. Plants were mowed at the soil line so that tuber skins can toughen for harvest. Mowing or killing vines, and delaying harvest for 2-3 weeks, also helps protect the tubers from late blight infection that could spread from above ground parts. UV light helps to break down spores over time. No Late blight was found on this farm in 2015. Carrots: Workers on the farm found fairly large (2 ) hornworms hidden in the soil while weeding the planting. They were quite numerous and we are trying to determine what species of hornworm they are, and if they are eating the carrot tops. There seem to be no species listed that feed exclusively on carrots but the food source of some local species has not been
determined or have wide host ranges. Hornworms are the larvae of sphinx or hawk moths. These moths have very tapered wings, are strong flyers, and resemble small bats while in flight, especially larger species such as the tomato hornworm. Hornworm found in carrots Liz Cecarelli, Eve s Corner Garden, Bethany, CT [reported by JB] Brassica crops: cabbage aphids and whiteflies were found. Whitefly on Brassica
Tomatoes: Septoria leaf spot is getting bad. This disease is hitting most tomato fields in the state this year and seems to be very aggressive despite the dry conditions. Max and Kerry Taylor, Provider Farm, Salem, CT [reported by J.B.] Rutabaga: Max found what looks like Brassica downy mildew on his rutabaga crop. It is a particular problem on radishes because it can damage the roots, and their radishes are planted right next to the rutabaga. I will bring it to Joan Allen at the UConn Plant Diagnostic Lab for confirmation. This is not the same species that attacks cucurbits or the basil species and cannot spread from those crops to Brassica crops. Use resistant varieties. Broccoli: Some plants were infested with cross-stripped cabbageworms. Max will use the 20% threshold to determine if and when he needs to spray for worms. Potatoes: Max and Kerry trialed several late blight resistant tomato varieties and were particularly interested in the larger varieties like Mountain Merit and Defiant. Now that the plants are loaded with fruit and can compare them, they have a strong preference for the larger and more uniform Defiant for future plantings. Potatoes: The tops of their early-planted and row-covered potatoes have already died back and they are waiting a couple of weeks for harvest to let the skins cure and toughen. They have dug the tubers from a few plants and can tell that they have more and larger potatoes than they ever had before when plants struggled with severe leafhopper damage. However, proof will be in the harvest. They are withholding judgement about covering the vines all season until they see the yields from the whole field. Covering the vines made it tougher to control the weeds and there was plenty of grass under the covers. But then again, most of the farms I visited this week were having weed problems at this point in the season. Jonathan Janeway & Charlotte Ross, Sweet Acre Farm, Lebanon, CT [reported by J. B.] Tomatoes: Septoria leaf spot is getting bad, as it is on so many farms. Cucumbers: light colored leaves that look nitrogen deficient. No sign of disease, but no set after the first fruit matured. Winter squash: high levels of squash beetles are killing some of the leaves and marking the fruit. PyGanic may help lower the levels to avoid direct damage on the fruit. squash beetle damage to fruit
Potatoes: The potatoes were grown under Proteknet, a non-heating type of exclusion cover for insect control only, not for earlier crops. They have been harvesting some to sell new potatoes and the tubers are full-sized, and yield has been good. Jude Boucher, UConn Extension UMass Vegetable Notes reported this week that bacterial canker was confirmed in pepper in VT causing total crop loss. It was likely seed-borne. This is the first report of this disease on peppers in New England. A couple of years ago, we reported in UConn s Crop Talk Newsletter that this disease had expanded its host range to peppers in British Columbia, Canada. One more reason for hot water seed treatment. That s all for this week. I ll send another update on Friday, August 28th.