Jul 26, 2012
Cotton Blooms - Photo by L Gallegos
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.
Aphid mummies and parasites. Photo: JK Clark
- 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
