Institute of Food and Agricultural Sciences
Hendry County Extension P. O. Box 68 LaBelle, Florida 33975-0068 Phone (941) 674-4092
VEGETABLE PEST AND DISEASE
November, 24, 1998
Bacterial spot has flared up on tomatoes and peppers as the result of heavy rains accompanying tropical storm Mitch. Distribution is generally widespread throughout the area. Infection incidence and crop damage levels range from generally light - moderate but is quite severe in some cases. Where races have been determined - races 1, 4, 5 and 6 have been isolated in pepper, bacterial race 3 has been isolated in tomato - this race is characterized by the diagnostic shot-holing on foliar lesions.
Early Blight/Alternaria and target spot are present at low levels on tomato, especially on older crops where the vines are relatively thick and foliage dense. Incidence is spotty and damage is generally low, although isolated fields have been hard hit by target spot. Continued heavy morning fog and night dews many encourage the spread of alternaria, which is often masked by the presence of bacterial spot lesions.
Target spot has also been identified on cucumber in a few isolated locations.
Broad mites continue to torment pepper growers as a result of relatively hot dry weather. Distribution is wide spread but localized, with numbers and crop damage reaching moderate to high levels in some fields.
Fall/beet/southern armyworms are widely distributed throughout the area. Incidence and damage levels are generally light in most fields. Worm pressure appears to be on a downhill trend with numbers falling off. An occasional tomato fruitworm has been spotted.
Leafminers are beginning to be seen widely across the area. Incidence and crop damage is low at present. Pressure from this pest will most likely increase over the next couple months as we enter the cool season. On the plus side, beneficial parasite numbers are up and should help control the situation if managed properly.
Pepper weevils are generally present at very low levels throughout most of the area, although localized incidence of fairly high populations and crop damage has been reported from some early fall pepper plantings.
Thrips are present on pepper in scattered locations throughout the area. Incidence and crop damage is reportedly at low levels to date.
Powdery mildew is widely present on squash. Incidence and crop damage increase with the age of the field.
Hot, wet conditions at planting time contributed to a high incidence of potato seed pieces rotting in the field before emergence, resulting in some fields having to be replanted.
Late blight has not yet been reported in the area. Heavy dews coupled with foggy morning conditions and warm temperatures may provide optimum conditions for the appearance of this disease.
Tomato yellow leaf curl virus update: TYLC has made a dramatic comeback in some parts of the state after generally low levels of occurrence last season. In the Gainesville area, some commercial fields have 100% of the plants displaying disease symptoms. In the Manatee/Ruskin area, a few fields had approximately 5% disease incidence early in the season and since that time infection rates are nearing 90% in those fields. In Homestead, some plantings have up to 50% disease incidence. SW Florida has been fortunate. To date, we have had only one commercial field with symptomatic plants at only 1% disease incidence. This disease has been termed an “urban disease” - in that it has been most severe in where both farms and residential populations are close together. Whitefly control in the field and plant house is critical to preventing TYLC from becoming a problem in SW Florida. For more info on TYLC: contact the Hendry County Extension Office, SWFREC or visit the UF website – http://hammock.ifas.ufl.edu/new/pg08400.htm.
Whitefly counts are reported to be up on some older stands of tomato. Unusually high whitefly counts have also been observed in isolated pepper fields. With the fairly high incidence of TYLCV being reported from the Homestead, Manatee/Ruskin and Gainesville areas, this may become a concern to local growers. Imidacloprid (Admire/Provado) has given excellent whitefly control to date. In addition growers are urged to: (1) Destroy fall crops early, (2) Control whiteflies at time of crop destruction (addition of oil and insecticide like Thiodan to herbicide), (3) plant spring crops late, (4) locate spring crops away from old plantings, (5) use transplants from uninfested areas, and (6) protect spring crops early from whiteflies
Contributors include: Fred Heald/Farmers Supply, Norm Kerr, Leon Lucas/Glades Crop Care, Gene McAvoy/Hendry County Extension, Chuck Obern/C+B Farm, Dr. Pam Roberts/SWFREC, Wes Roan/6 L’s, Jay Shivler/ F+F Ranch, Dr. Phil Stansly/SWFREC and Dr. Charlie Vavrina/SWFREC.
The SW Florida Pest and Disease Hotline is compiled by Gene McAvoy and will be issued on a biweekly basis by the Hendry County Cooperative Extension Office as a service to the vegetable industry.
Extension Agent II
Vegetable/Ornamental Horticulture 941-674-4092 phone
Hendry County Extension Office 941-860-8811 mobile
PO Box 68 941-674-4097 fax
LaBelle, FL 33975 firstname.lastname@example.org
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COOPERATIVE EXTENSION WORK IN AGRICULTURE, FAMILY AND CONSUMER SCIENCES, SEA GRANT AND 4-H YOUTH, STATE OF FLORIDA, IFAS, UNIVERSITY OF FLORIDA, U.S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS COOPERATING