Five Tips For Better Tomato Disease Control

The best tomato disease control involves diligent scouting for damaging pests.

Phil Stansly, Ph.D., professor of entomology with the University of Florida, says tomato disease control is a top concern for Florida growers.

Tomato yellow leaf curl virus (TYLCV), transmitted by the silverleaf whitefly, is the primary threat for Florida’s spring crop and a concern for south-Florida growers who have seen a spike in the magnitude of whitefly outbreaks in recent years.

“Increased disease pressure, especially if it comes early, can ruin a crop,” says Stansly. “If viruses appear within a month of transplant, growers could lose as much as 50 percent of the crop.”

To help growers protect spring tomato crops and produce high-quality, marketable fruit, Stansly highlights five key elements of an integrated pest management (IPM) plan for tomato disease control.

1. Be Selective

TYLCV causes stunted growth and poor fruit set. In the southern growing region of Florida, whitefly populations may explode as early as February. To be safe, Stansly recommends area growers select TYLCV-tolerant tomato cultivars for the spring crop. Recent evaluations of TYLCV-tolerant varieties in south Florida can be found by searching for “TYLCV” at the Southwest Florida Research and Education Center website under Vegetable Horticulture.

2. Space Crops

Stansly recommends allowing a four- to six-week resting period between harvesting the fall crop and planting the spring crop. At planting, avoid placing plants into or adjacent to fields previously planted with whitefly host crops. “If you have an older crop such as tomato, pepper or cucurbit still in the ground, you want to plant the spring crop as far away as possible,” advises Stansly. “Otherwise whiteflies could easily move from the old into the new crop.”

3. Keep Fields Clean

Field sanitation is a critical component of a pest-management strategy. Stansly recommends completely destroying crop residue within five days of harvest. For a thorough job, consider applying an insecticide directed at adults, such as a pyrethroid, organophosphate or endosulfan to suppress existing whitefly populations, followed by a burndown herbicide application to remove the host crop. Finish by turning under residue.

4. Start Strong

To give plants the best start in the field, treat with pymetrozine while in the transplant house, followed by a neonicotinoid application just before transplant to protect crops as they enter the field. A follow-up neonicotinoid drench immediately after planting will provide whitefly protection for up to eight weeks.

5. Guard Against Enemies

After planting, inspect plants for insects and make an insecticide application when action thresholds are reached. After the initial neonicotinoid drench, Stansly cautions growers to switch to a non-neonicotinoid insecticide for the remainder of the cropping period to slow pest selection for resistance.

Management Options

The best way to deal with fungal disease is to prevent them. A timely fungicide application prior to infection is the best way to control target spot. DuPont™ Fontelis® fungicide provides excellent control of target spot in tomatoes and other fruiting vegetables, as well other fungal diseases, including Alternaria blights and leaf spot. Fontelis® can be applied at 7- to 14-day intervals, depending on disease pressure, provides excellent crop safety and is rainfast within one hour of application.

A selective insect control solution, such as DuPont Coragen® insect control, provides long-lasting protection against damaging worms and leafminer larvae and suppression of silverleaf whitefly nymphs says Dan Sherrod, product development manager for insecticides, DuPont Crop Protection. It also has minimal impact on beneficials to conserve natural enemies and enhance biological controls.

“The beauty of Coragen® is that it has an excellent environmental profile along with powerful systemic activity,” says Sherrod. “An application of Coragen® at the root zone allows the active ingredient to be easily taken up by plant roots and delivered to the foliage.”

By following these practical IPM tactics and maintaining adequate crop moisture, growers will promote a fruitful spring crop.

 

See product labels for specific crop/pest combinations controlled or suppressed.

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