- Author: Peter B Goodell
Useful resources:
On-line training for Year Round IPM Programs
Cotton Pest Management Guidelines
The UC Statewide IPM Program has announced the availability of an on-line tutorial to aid in the use of Year Round IPM Programs.
The on-line training series provides seven video chapters as a "guided tour" of the benefits and uses of the Year-Round IPM Program in field, orchard, and vineyard crops. All the videos except the introduction contain short interactive quizzes.
The seven chapters include:
- Introduction
- Prevention
- Pest identification
- Monitoring
- Management decisions
- Management methods
- Environmental concerns and summary
The on-line training can be reached by clicking here
- Author: Peter B Goodell
Useful cotton monitoring and treatment guidelines:
The season thus far has been good, even with a delayed planting. Almost every cotton field is nearly at a similar same stage of development, has good fruit development and retention and is facing low Lygus bug threats. Flowering continues to move up the plant as it turns its attention from vegetative to reproduction by filling bolls and developing lint.
What are the pest management issues that could come into play?
- Lygus: our experience and the literature indicate that Lygus is less of a threat during July and August than in June. While field should continue to be monitored weekly, cotton plants with excellent fruit load will be shedding fruit due to physiological rather than due to Lygus feeding. Population levels which can be tolerated are 7-10 bugs/50 sweeps with the presence of immature Lygus.
- Aphids and whiteflies: Always a potential threat during August which is why a weekly field inspection is so important. Sample 5th leaf from top looking forincipient colonies. See earlier Post for details. A key natural enemy are wasp parasites, which are commonly being seen attacking cotton aphids. Look for dried, empty shells of aphids with circular emergence holes.
- Spider mites: these were a problem last year so continue monitor the fields, especially near dusty roads or sources of mites, such as corn or almonds. For management details, see Cotton Pest Management Guidelines
- Author: Peter B Goodell
Useful links:
- Common Natural Enemies: Your Allies in IPM of Cotton
- Common Whiteflies in SJV Cotton
- Aphids Common to Alfalfa and Cotton
- Sampling Whiteflies in 7 Minutes or Less
- UC IPM Pest Management Guidelines for Aphid in Cotton
- UC IPM Pest Management Guidelines for Whitefly in Cotton
However, whiteflies and aphids are always present and can cause major problems if not watched carefully.
There are a number of aphids and whiteflies that could be found in cotton and our IPM focus has been on proper identification of sweetpotato whitefly (or silverleaf)and cotton (or melon) aphid.
Dr. Peter Ellsworth, IPM Specialist with University of Arizona Cooperative Extension and his colleagues have produce a great one page factsheet reminding us of the sampling procedure for whiteflies in cotton. This procedure is a binomial process which removes the requirement to count every insect on the sample leaf. It requires the 5th leaf from the top to be selected and the entire sampling activity can be conducted in 7 Steps in 7 Minutes. Click here to read the leaflet.
The AZ approach has been adopted by UC Pest Management Guidelines for Cotton and the 5th leaf is the same sample unit for cotton aphids. While aphid honeydew has a different
- Author: Peter B Goodell
- Year round IPM Program for Cotton: Early Squaring Activities:
- Monitor Cotton Growth – Early Squaring
- Monitoring to Make Lygus Decisions
- Calculate Expected Square Retention
- Cotton Field Check (June 2011) - Why the Cotton plant is the Great Indicator for Lygus Management
For San Joaquin Valley cotton growers, one of the most important production decisions is to get the plant into a vigorous fruiting cycle and to hold the early fruit so the plant is manageable for the remainder of the season.
During the earliest fruiting period, retention of fruit on the first 10 fruiting branches is top priority and the most difficult to interpret. We understand the Acala Upland retention very well but are stretching the data for Pima. However, using the Acala data developed over 20 years ago provides valuable guidelines in evaluating fruit loss and retention.
June is a critical month to manage Lygus but once the initial fruit is set and bloom occurs, greater densities of Lygus can be tolerated. If June treatments are required remember to:
- Make sure the fruit loss can be related to Lygus;
- Lygus are present
- Selective products are utilize to preserve the natural enemies already in the field
- Practice good insecticide resistance management practices and take care to not over use any particular active ingredient
- Author: Peter B Goodell
Useful resources:
- Information leaflet
- Identification videos
- General Fusarium information
- UC IPM Cotton Pest Management Guidelines
Fusarium Wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is a widespread disease causing damage to a wide host of crops. Until recently, cotton was affected only through the association with root knot nematode. However with the emergence of Race 4, its presence has been felt throughout the San Joaquin Valley.
Current research efforts by USDA-Ag Research Service and University of California Agricultural Experiment Station and Cooperative Extension is working hard to find ways to manage this disease. Thus far, breeding for resistance and tolerance to the fungus is the most promising approach.
In order to use the variety best suited for your situation, knowledge of the infestation is required. This early period of plant development (emergence to first fruit) is a good time to watch for symptoms in the field. In seedlings and young plants, cotyledons and leaves wilt and drop, resulting in bare stems. In severe cases, plants die. In mildly affected plants, lower leaves develop symptoms but plants survive, but with reduced vigor. Look for breaks in the plant stand with associated dead or drying plants. Other symptoms include a general wilt, which is especially evident on warm days, and yellowing and necrosis of lower leaf margins. The vascular system of infected plants is brown. This is most apparent in the lower stem and upper taproot.
The UC CE Cotton Team has developed valuable information for identification and management of Fusarium Wilt Race 4. The UC CottonInfo website provides current information including UCcottoninfo Channel on YouTube. Bob Hutmacher and Brian Marsh have developed a video about “how to” look for disease symptoms, including which plant to sample which is very helpful.
COMMENTS ON THE DISEASE - From UC IPM Cotton Pest Management Guidelines
Four genotypes (called races) of Fusarium oxysporum f. sp. vasinfectum presently occur in California. Races 1, 3, and 8 are mildly virulent and cause few, if any, symptoms on cotton unless the plants are also infected with root knot nematodes. Race 1 is widely distributed in the San Joaquin Valley; races 3 and 8 are found in a limited number of fields in Tulare and Fresno counties. Race 4 is significantly more virulent and can cause severe symptoms on certain Pima varieties and mild to moderate symptoms on most Acala varieties. Seedlings of susceptible Pima varieties often die and resemble plant losses caused by damping-off fungi. Stand establishment in some fields is markedly reduced. The distribution of race 4 is not fully known, but it is becoming more common in Fresno, Tulare, Kings, and Kern counties.
The fungus sustains itself on the outer surface of roots of many crops and weeds and survives indefinitely in soil. In addition, the pathogen is seed-borne in cotton, which accounts for long-distance spread, and is also spread whenever infested soil is transported on boots, farm equipment, in flood irrigation, etc.