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
April 15, 1999
Severe drought continues to plague southwest Florida. No precipitation has been recorded at the FAWN weather station in Immokalee in over a month. Dry conditions have been exacerbated by rising daytime temperatures, which have been in the high 80’s and even the low 90’s over the past few weeks. Night temperatures are finally beginning to rise to more seasonable levels with the mercury reaching the mid to upper 50’s and low 60’s over the past two week period. High temperatures combined with breezy conditions and low humidity have resulted widespread moisture stress manifesting itself in terms of poor growth, low vigor, reduced yields, smaller fruit size and compromised fruit quality. Tomato ripening has been greatly accelerated by the heat and drought and the spring crop promises to be a short one. Sunscald is causing concern to pepper growers.
Many growers are now reporting difficulty in maintaining adequate soil moisture levels for optimum crop growth. A number of experienced growers are indicating that the current drought is one of the worst that can be remembered. Drought related problems being reported include salt injury to crops in some isolated cases, floral abortion, and a widespread increase in the level of blossom end rot on tomatoes and other crops among other problems listed above.
Armyworm counts are on the rise across the area. A number of growers are reporting significant increases in beet armyworm and southern armyworm in tomato and pepper. Although sprayable thresholds have been reached in a number of cases, crop damage has been minimal to date.
Pinworms are widely present and increasing on tomato. Pheromones appear to be working for the most part although some respondents are reporting that they have had to resort to harsh chemicals in order to obtain control. There have been no reports of fruit damage.
Several reports of pickleworms have been received from widely scattered sites. Rindworm damage – attributed mostly to southern armyworms and tomato fruit worms - has been noted on melons. Crop damage has been minor for the most part although again growers are reporting having to use harsh chemicals to obtain control in some cases.
High whitefly counts are being reported from a number of locations on cucurbits and tomatoes and seem to be on the increase, however some respondents are noting low whitefly populations especially in tomato. In some older melon plantings, whitefly numbers have reached sufficient levels to cause sticky rinds.
Diamond back moths are being seen sporadically in brassicas along with fair numbers of loopers being reported on tomato.
Pepper weevils continue to build across the area particularly in older fields. Some respondents indicate that despite the continued presence of weevils, they are largely under control.
Leafminer populations continue to decline, although there have been a few reports of new mines in the upper canopy of tomatoes where pest control measures had been minimized in response to low tomato prices. This is largely in older fields, which are being harvested, and so poses little problem.
Downy mildew and powdery mildew are present on cucurbits across the area. Powdery mildew has been the most severe with some defoliation occurring but this has mostly been on older fields where the crop is being harvested. Yields should be little affected. New reports of downy mildew on cantaloupe have come from one respondent.
Mosaic is continuing to increase on melons across the region. Some fields have reached moderate to high infection levels but crop losses should be minimal, as the crop has already been made in most cases.
Gummy stem blight is widely present on watermelon through out the area. Incidence is mostly low to moderate.
Fusarium wilt continues to be reported widely on watermelon. In most instances, only scattered plants are being affected in any particular field, although there have been some isolated cases where losses have been moderate to high. In at least one instance, fusarium rot has been positively diagnosed on watermelon fruit. The incidence of fusarium crown rot in tomato has also shown some increase over the past few weeks.
Spider mites are increasing on tomatoes and cucurbits. Populations are highest in driest areas along roadways and field margins. A number of growers are reporting the highest levels in several years.
Broad mites appear to be trying to make a comeback on pepper in a few locations.
Persistent but sporadic, low levels of aphids have been observed in many areas on brassicas, cucurbits, pepper, potato and tomato.
Flower thrips (F. bispinosa) are widely present and appear to be increasing somewhat in certain locations on pepper and tomato, while declining or stabilizing in others. Melon thrips (Thrips palmi) are causing low to moderately low damage in some fields.
Tomato yellow leaf curl virus is widely present on tomato across the region but levels appear to have stabilized in the 2- 5% in most cases. This situation should not lull growers into complacency. Growers need to be sure to clean up spring fields quickly. It is not too early to start preparations for a clean summer fallow. It will take all growers cooperation to avoid over-summering tomato plants and creation of whitefly breeding grounds.
Calendar of Up-Coming Events:
May 6, 1999 – Vegetable Field Day – SWFREC - 10 AM to Noon – focus on Spring Research Trials
May 12, 1999 – Vegetable Meeting – SWFREC – 6 PM to 8:30 PM – Methyl Bromide Alternatives –Fumigants
May 13, 1999 – FACTS Sprayer Field Day – SWFREC – 10 AM to 3 PM – Sprayer calibration, demonstrations and more.
Contact the Hendry County Extension Office for more information.
An Aquatic Weed Control,
Aquatic Plant Culture and Revegetation Short Course will be held at
the Fort Lauderdale Research and Education Center from May 17
–20, 1999. Up to 24 CEU’s may be earned.
Contact Dr. Vernon Vandiver at 954-475-8990 or email@example.com for further information.
Contributors include: Earl Bone/Pero, Kathy Carbiener/Severts, Cleitus Childers/Sunnyland Farm, David Harloff/Pacific Tomato Growers, Fred Heald/Farmers Supply, Sarah Hornsby /AgriCropCon, Britt Keene/6L’s Leon Lucas/Glades Crop Care, Gene McAvoy/Hendry County Extension, Alice McGhee/Thomas Produce, Chuck Obern/C+B Farm, Dr. Pam Roberts/SWFREC, Wes Roan/6 L’s, Kevin Seitzinger/Gargulio, Mike Stanford/MED Farm, Dr. Phil Stansly/SWFREC, Don Tanner/Country Boy, and Dr. Charlie Vavrina/SWFREC.
The SW Florida Pest and Disease Hotline is compiled by Gene McAvoy and is issued on a biweekly basis by the Hendry County Cooperative Extension Office as a service to the vegetable industry.
Special Thanks to the generous support of our sponsors; who make this publication possible.
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