Useful Resources:

• UC Pest Management Guidelines for Cotton
• Whitefly Management Guide
• Whitefly Webinars, Plant Management Network

August is the typical time for change in managing cotton pests in the San Joaquin Valley. As the plant is shifting from setting fruit to maturing fruit and our attention is shifting from protecting yield to protecting quality. Lygus becomes much less of a concern as bolls mature beyond 10 days after flowering and our attention focuses on preventing excessive honeydew from drifting down onto open bolls and exposed lint.

 Minimizing the occurrence of sticky cotton remains a critical goal for San Joaquin Valley cotton.  Close attention to fields

In the past several years, a resurgence in sweetpotato whitefly biotype B (formerly silverleaf)  has been experience in the San Joaquin Valley. I am noting a very preventative approach in managing whitefly with treatments being applied at very low population densities. The concern for sticky cotton is real and the response to prevent it is understandable.

PCAs and growers should consult regularly to review their individual situations, determine a course with the remainder of the season in mind, and select insecticides based on the threat, the population composition and insecticide resistance principles.

There is a good collection of information available and the interested pest manager is directed to these list above for more details.

There have been numerous reports of pale striped flea beetle in cotton around the Five Points area of Fresno County. Population densities of 20-30/50 sweeps have been found, causing some concern among PCAs. The most common species is the pale striped flea beetle, Systena blanda.

In most cases, flea beetle is usually a problem on seedling cotton, not on blooming cotton according to IPM Manual for Cotton in the Western US.

The manual states: "Flea beetles, small beetles with enlarge hind legs that enable them to jump, chew small round holes or pits in cotyledons and young leaves. They

Pale striped flea beetle bract damage

However, given enough beetles moving into a cotton field at one time, damage can occur. One field I observed in late July had over 500 beetles for 50 sweeps and caused considerable leaf damage in the lower canopy. The source of beetles were neighboring alfalfa fields which were recently cut and water stressed.

Damage to the leaves was mainly superficial feeding. Leaves were not tattered nor did they display

Pale striped flea beetle leaf damage on cotton

While not normally a damaging pest to mature cotton, high population densities of pale striped beetle can potentially cause damage at any stage of growth.

Damage to cotton caused by pale striped leaf beetle

Useful resources:

• Monitoring Lygus in cotton
• Stripping alfalfa hay
• Movement of Lygus in the Landscape
• Natural enemies in cotton

        With growing conditions continuing to look favorable for cotton growth and development, fruiting is beginning or well underway in some locations. Fruiting is being noticed in Firebaugh area at 6^th main stem node, which is line with early season temperatures we have experienced and good planting dates.

        Setting the early fruit sets the plant up for the rest of the season. With a shortage of the irrigation deliveries this year, the season must be as compact as possible. Protecting early fruit is critical in these water short conditions.

        Lygus will be a localized problem. Movement will occur from neighboring sources, most likely other cultivated crops. Key sources for Lygus include safflower, forage alfalfa and seed alfalfa. Within safflower and alfalfa forage, the Lygus population can be managed to prevent mass movement into surrounding cotton fields. Lygus is closely managed in seed alfalfa can still acts as a major source.

        Safflower is currently being treated for Lygus to prevent the first generation from

        Alfalfa forage is the most common crop which Lygus prefers. It is a unique crop in our cotton landscape because it is harvested frequently for its vegetative biomass, not its reproductive parts, e.g. fruit, lint, seed. Providing even a limited habitat during cutting can have a substantial effect on mitigating Lygus movement into cotton. During the June and July cuttings, if uncut strips of alfalfa are left in the field, Lygus will move to them and stay until the next irrigation cycle, when they return to the larger alfalfa field.

         Limiting the movement of Lygus into cotton not only protects the fruit during this critical early stage but can reduce the need for insecticide applications. This allows additional natural enemies to build and helps reduce pressure for the development of insecticide resistance.

        Early intervention through the cultural control of Lygus source management will help set the cotton up for high fruit retention, shorter season and fewer secondary insect and mite problems, as well as reduce costs in early insecticide treatments.

Useful resources:

        On-line training for Year Round IPM Programs    

        UC IPM  website

        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:

1. Introduction
2. Prevention
3. Pest identification
4. Monitoring
5. Management decisions
6. Management methods
7. Environmental concerns and summary

The on-line training can be reached by clicking here