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

may be present on older plants, where they feed on leaves and flower bracts.. ".

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

open holes, rather the upper surface was removed. This caused the tissue to die and many leaves to drop off the plant.

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.

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.

        The lack of rainfall during January to March should limit the severity of Lygus. While there are weed hosts, mostly short pod mustard, along roadsides and in many dryland grain fields, most hosts were limited in their ability to establish in a wide area.

        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

reaching adulthood and breeding or flying into neighboring fields. In recent years, most safflower has successfully been managed to prevent Lygus from infesting cotton. However, management in the future will become more challenging as the few available insecticides are difficult to procure and more reliance is being placed on fewer active ingredients. For many growers, safflower plays a critical role in their crop rotation which addresses key environmental issues related to groundwater protection.

        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.

Year Round IPM Programs were developed as another means to retrieve information from the comprehensive Pest Management Guidelines. While the Guidelines are organized by pest, the Year Round Program condenses a year's worth of management activities for key pests into one checklist arranged by season or crop stage. Over half the crop groups in the Guidelines have a Year Round program associated with it, cotton being one.

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

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

Sticky cotton is a condition the San Joaquin Valley cotton growers have been able to avoid in most years, due to no small contribution of natural enemies which prey and parasitize these pests.

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 5^th 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 5^th leaf is the same sample unit for cotton aphids. While aphid honeydew has a different

constituency than whitefly, both can damage lint quality and cause major harvest, ginning and spinning problems. Details of aphid and whitefly sampling can be found in the Cotton Pest Management Guidelines.