Cooperative Extension Service 
________________________________________________
Institute of Food and Agricultural Sciences
 

Hendry County Extension P. O. Box 68 LaBelle, Florida 33975-0068 Phone (941) 674-4092

SOUTHWEST FLORIDA
VEGETABLE PEST AND DISEASE
HOTLINE

March 4, 1999

A series of weak cold fronts pushed through the region over the past two weeks bringing drier air and dropped average temperatures to the mid to upper 70's days and mid 50's to lower 40s at night.  Several nights saw temperatures dip into the high 30s.  Precipitation was minimal during this time. The FAWN weather station at Immokalee recorded .18 inches of rain on March 3rd.  Up to .35 inches were reported from east Naples and Devil's Garden.   The cooler drier weather has resulted in a moderation of disease and insect pressure.

Pepper weevils populations are building up rapidly in a number of locations across the area, particularly in older plantings and specialty peppers, although they have also been noted in some young fields as well.  Growers should monitor populations with pheromone traps. Look for adults during the early morning hours in the top third of the plant, as weevils retreat into the canopy later in the day.  Be sure to check fallen fruit for weevils, frass, or damage.  Vydate is probably still the best product for control. It is only effective on adults so that established infestations must be sprayed regularly to kill adults as they emerge. Sanitation is important as weevils move from old fields to infest new plantings. Destroy old fields after harvest.  Be sure to spray fields before destruction and thoroughly incorporate crop residues.

Late blight has now been positively identified on tomato in few locations around Immokalee. Lab analysis has positively identified one sample as US 8 a potato strain and another US 17 a tomato strain, which was very active in this area several years ago. Since temperature and moisture conditions conducive to the development of the disease are present throughout most of our growing season), growers are advised to apply protective fungicides before infections are identified in the field. Note: Florida has been granted Emergency Exemption Section 18 label for Tattoo C to control late blight on tomato. This expires May 20, 1999.

Late blight remains widely present on potato around the region. Infection levels are low to moderate. Reports indicate that the disease appears seems to be under control in most fields with little active sporulation being noted in most fields.  Some increase in incidence is being reported in some cases.

Gummy stem blight is being reported widely on watermelon.  The diagnostic lab at SWFREC has reported an increase in positive sample for this disease. Infection levels are generally low to moderate. Favorable weather conditions and judicious control programs seem to have slowed disease progress in most cases.

Downy mildew is also present on cucurbits and has been identified in a number of locations including Immokalee, Devils Garden and Alva.  Incidence is generally low although some spread has been noted in places.  For those with internet access, Dr. Gerald Holmes of North Carolina State maintains a very informative Cucurbit Downy Mildew Forecast web page which projects both trajectory and threat outlooks several times per week.  The web address is http://www.ces.ncsu.edu/depts/pp/cucurbit/.  The site also features information on the disease.

Downy mildew is also widely present on cole crops across the area.  Incidence is high in some fields and crop damage low to moderate.

Pinworms are being caught in traps in scattered locations across the area. There have been very few reports of pinworms or eggs being found on plants.  Pinworms are traditionally a late season problem in our area.  Pheromone traps should be used to monitor populations and growers should apply pheromones at high rates to disrupt mating once threshold levels of 3-5/trap/night are reached.  In the case of well-established populations insecticides like Spintor and AgriMek are the only recourse.

Scouts are picking up a few diamondback moths in brassicas.  Otherwise, little worm activity has been noted.

High whitefly counts are being reported from a number of locations on cucurbits, eggplants, potatoes, and tomatoes, while in other locations respondents are noting very low whitefly populations.  The situation is rather mixed up but is of major concern due to the presence of TYLCV throughout the area.

TYLCV is widely present across the area. In general, the incidence of infection is rather low but from all reports appears to be slowly increasing with 1 2% infection rates being reported widely. A few fields have reached 5% infection levels. Several respondents are reporting the continued appearance of new infections despite very low whitefly counts. Growers are urged to maintain their vigilance in combating this disease and it's whitefly vector to avoid the buildup of TYLCV to levels being observed in other areas of the state.  For more information on TYLCV and whitefly management contact the Hendry County Extension Office.

Isolated cases of other viral diseases including tobacco mosaic and potato Y in tomato and watermelon mosaic on watermelon have been reported.  Incidence and severity is low.

Scattered reports of broad mite on pepper continue to be received. Some increase in numbers has been noted. Incidence in any given field is spotty.  Depending on conditions, populations may begin to build as warmer drier weather returns to the area.

Leaf miner and thrips activity has been relatively quiet. Most respondents indicate these pests are currently under control.

Sporadic, low levels of aphids have been observed in a number of areas on brassicas, cucurbits, pepper, and potato.  On some days, winged aphids are common. Programs to control other pests seem to be keeping these in check.

Reports of isolated cases of sclerotina in tomato and pepper have been reported.

FAWN Weather Data from SWFREC Station/Immokalee for February 1998.
 
Date
Air Temp (F)
Rainfall
Hours below Certain Temperature
 
 Min
Max
 (inches)
40 F
45 F
50 F 
55 F
60 F
Dec 1998
41.4
86.3
1.12 
 0.0
10.6 
37.5
62.0 
91.2
Jan  1999
30.7 
85.2
1.50 
12.0
32.0
71.5 
114.4
213.6
Feb  1999
38.3 
84.3
0.37 
10.6 
46.5
88.8 
 140.4
208.7

Contributors include: Bill Bethea/Circle M Farm, Fred Heald/Farmers Supply, Sarah Hornsby /AgriCropCon, Leon Lucas/Glades Crop Care, Gene McAvoy/Hendry County Extension, Alice McGhee/Thomas Produce, Chuck Obern/C+B Farm, Wade Purvis/Silver Strand, Dr. Pam Roberts/SWFREC, Wes Roan/6 Ls, Jay Shiveler/F+F Farm, John Stanford,  Dr. Phil Stansly/SWFREC 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.
 

Gene McAvoy
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                                     gmcavoy@gnv.ifas.ufl.edu

The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity - Affirmative Action Employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin.
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

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