Vegetable Pest & Disease Update July 20, 2018 THESE REPORTS ARE BASED ON INPUT FROM SEVERAL NORTHEAST STATES INCLUDING NEW ENGLAND AND NEW YORK. YOUR CONTRIBUTIONS ARE WELCOME TO MAKE THIS REPORT MORE SPECIFIC TO CONNECTICUT AND TO SHARE INFORMATION FROM OUR STATE WITH OTHER GROWERS IN THE WHOLE REGION. PEST AND DISEASE OBSERVATIONS (AND PHOTOS ARE GREAT) CAN BE SUBMITTED TO SHURESH GHIMIRE AT shuresh.ghimire@uconn.edu. GOOD INFORMATION TO INCLUDE: CROP (INCLUDING CULTIVAR IF KNOWN), PREVALENCE/SEVERITY OF THE PROBLEM, CONTROL STRATEGIES USED, YOUR COUNTY. Alliums: Bloat nematode: Present on LI. Also on an Amish farm in Finger Lakes - likely from saved seed, originally from a now retired seed seller. None reported in other New England states so far. Photos: Cornell University Garlic rust: Present in NY. Can come in on planting material. Sporadic occurrences throughout NE over the past few years. Thrips: Extensive damage on onions in NH from conventional farm. Also in MA - onions and leeks. Extensive damage on onions planted on silver plastic. A reminder that silver plastic is not a cure-all. Hadn t been fertilized so plants weren t able to grow beyond damage. Grower didn t spray anything. Embellesia skin blotch: Diagnosed in NH. White rot diagnosed in garlic in ME. Suspected this is from saved seed grower had problems for several years. Bulb mites: lots in garlic in NH. Brassicas: Caterpillars of imported cabbageworm, diamondback moth and cross-stripped cabbageworm starting to be seen in CT this week. Cabbage aphids and flea beetles in MA.
Beans: Mexican bean beetle: Hampshire Co., MA. Small larvae becoming abundant. Farms releasing Pediobius now. Leafhopper: Lots of hopperburn in MA and RI. Chenopods: Cercospora leaf spot: Present throughout NY and also in CT. Not necessarily new this week. Incidence increasing this week. Leafminer: New eggs still appearing in MA. In general, beets are not enjoying the heat, with many being sold without the greens or bunched with just stems. Cucurbits: Cucurbit mystery across MA: MA: Yellowing and wilting in winter squash, across the state, over the past 2 weeks. Samples have been submitted to the diagnostic lab but no conclusions yet. No squash vine borer larvae in stems. Doesn t look like bacterial wilt (though we are seeing those symptoms now too). Cultured soft-rot bacteria from one sample with obvious soft-rot symptoms - Rob Wick suspected that wind-blown sand could injure plants and allow for entry of bacteria. Other plants without obvious soft-rot symptoms. Bacterial wilt: Found in winter squash in open field in CT (Litchfield Co.). This disease is caused by bacteria (Erwinia tracheiphila) that are transmitted to the plant by both spotted and striped cucumber beetles. More information on this disease can be found at this link: http://ipm.uconn.edu/documents/raw2/bacterial%20wilt/bacterial%20wilt.php?aid=92 Photos: Bacterial wilt in the field (left: Shuresh Ghimire), bacterial streaming (grainy looking area) from symptomatic leaf tissue (right: Joan Allen)
Squash vine borer: CT: Larvae being found in squash. Photos: UMass (left), Shuresh Ghimire (right) Detailed review of SVB can be found at the following link: https://extension.unh.edu/resources/files/resource004198_rep6024.pdf A review of SVB management in organic farms can be found at this link: http://articles.extension.org/pages/65684/biology-and-management-of-squash-vineborer-in-organic-farming-systems Cucumber beetle: declining in CT. Bacterial wilt incidence increasing. Squash bug: Nymphs hatching now in CT and MA. Powdery mildew: Present in CT and MA (Franklin and Middlesex Cos). Present in LI in earliest squash plantings. Take this weather opportunity to make preventative applications, because if you cannot find it today you will likely see it tomorrow. RI squash mystery: angular, speckled white lesions. Some on younger leaves but mostly on a specific age of leaves. Lesions with yellow halo. Mainly on jack o lantern pumpkins, some on pie pumpkins. On butternut on one farm; all new growth looks great. Wasn t raining when symptoms appeared. If it s bacterial, grower should see symptoms in new leaves after last night s rain. Herbs: Bacterial leaf spot and Alternaria dauci: Found on cilantro in NH. Grower has had problems before. First report of A. dauci from Florida this year. Planted very densely. Basil Downy Mildew: Present in MA, none reported in other New England States yet.
Japanese and Asiatic garden beetle adults continue their presence in CT. Japanese beetles are active during the day while Asiatic garden beetles are nocturnal and will be observed feeding at late hours during warm nights. During the day, Asiatic garden beetles hide in the soil or debris near the base of plants. Asiatic garden beetles can be a problem for basil and Japanese beetles can also be found also on basil in addition to beans and sweet corn. Solanaceous: Tomato: Flea beetle: Hampshire Co., MA: Lots of flea beetle in high tunnel tomatoes, causing significant damage to foliage. Look like different species, smaller. RI: have seen flea beetle in field tomatoes but not much damage. NY: lots in one field in potato, a little in eggplant. Totally took out potatoes. Botrytis in high tunnel tomatoes in RI. Powdery mildew: Very bad in high tunnel tomatoes in RI. Present in small amounts on LI. Leaf mold: None in RI. Present throughout MA. Tomato spotted wilt virus: Appearing now on LI - top growth will brown, ring spots. Pith necrosis in field tomatoes in NY. Also in plants waiting to be transplanted - a little overgrown. Odd to see it in young tomatoes without substantial stems. Rhizoctonia in field tomatoes in research plot in RI. Planted 2 weeks ago. Likely carried over from flats. Hornworm present in Hampshire and Worcester Cos, MA and in RI peppers. Blossom end rot: Incidence increasing in tunnel tomatoes in CT. Leaf curl: Lots in CT, even in irrigated plantings. Suggested to put in moisture sensors in high tunnels, so that growers get a better sense of how much to irrigate - maybe more than they think. Bacterial canker: In field and high tunnel tomatoes in NH.
Eggplant: Verticillium wilt: Diagnosed this week in CT, last week in MA. Photo: UMass Extension Flea beetles: Very bad in RI. Pepper: Pepper maggot: none reported in CT. Oviposition marks scouted yesterday in Middlesex, Co, MA. 4-lined plant bug damage in peppers in RI. Create distinct circular dark lesions on leaves after feeding. 3-lined potato beetle: lots in ground cherries in RI. Potato: Leaf hoppers are in low numbers currently, but are around. No hopper burn noted as of yet. Sweet Corn: Of the four sites so far reporting in MA, no European corn borer captures, 3 have corn earworm traps, also no captures, one has a western bean cutworm trap which has a capture of 13. Sap beetles catching people off-guard in early corn in NH. Usually appear later in the season. Happening in MA too. Not high numbers but concerned about early timing. Other crops: Deer taking out sweet potato plantings in NH. Tarnished plant bug: More than in previous years? Not doing tons of damage but important to pay attention to if populations are increasing. NH and MA.
Good News- what is going well? Overall, nothing seems to be out of the ordinary and there is a near perfect weather window occurring to allow for preventative applications to be made for diseases. Take advantage of this opportunity, which should help the rest of your season. Cucumber plants look healthy in a farm in Litchfield, CT. Photo: Shuresh Ghimire