A Wedge-Shaped Wonder

06-13PGcvrThis long-named, small insect has risen to the status of key pest.
Whether you abbreviate its name as TCAH or 3CAH, the threecornered alfalfa hopper continues to hop squarely on the level of key pest in at least some peanut fields each year. It is often the pest that triggers the first insecticide treatments and management decisions for TCAH are most often judgment calls coupled with the producer’s own level of tolerance.

Readily Visible Damage
Often described as triangular or wedge-shaped, this insect has piercingsucking mouthparts for feeding. TCAH has the habit of feeding in a circular pattern around the stems and leaf petiole, resulting in girdling the affected area, thus reducing the downward flow of nutrients to the roots and pods. Often, there is purpling or reddening of the stem above the feeding site. If the stem is severely damaged, the plant may respond by producing adventitious roots around the damaged area in an attempt to compensate for the lack of nutrient flow.

Multiple feeding sites can often be found on the same stem, and the result can be severely restricted sugar transport. Blooms, pegs and pods beyond the affected area may be deprived of needed nutrients.

Multiple Hosts
This pest is not picky as to its host plant, and besides peanut, it will feed on vegetables, soybeans, alfalfa, corn, sorghum and other grasses and legumes. TCAH stay the winter as adults around field borders or as eggs in plant tissue. Adults and emerging nymphs usually migrate into peanuts in June and July.

Nymphs develop into adults within several weeks, which give rise to the potential for two to three generations per crop year. Both the adult and nymphs feed on stems, leaf petioles and pegs when populations are excessively high. Extensive feeding can negatively affect yields.

‘If-Then’ Treatment Options
The first migration of adults, which often occurs in late June and early July, would be the best opportunity to control the egglaying adult population and limit subsequent, and most damaging, nymph populations. The judgment is whether there are enough TCAH in the early populations to warrant a treatment. If there is one adult per foot of row, then treat. If there is only one per three feet of row, and if this is the only limiting factor in high-yielding peanuts, then one might choose to piggyback a treatment with a fungicide application.

If you have experience with varietal responses to TCAH, then it is better to yield to your best judgment given your varieties planted. If peanuts are within 30 days of digging, do not treat. PG

New Addition To The UGA Peanut Team
The peanut industry welcomes a new member to the University of Georgia Peanut Team. Dr. Mark Abney, from North Carolina State University, will start as UGA Peanut Entomologist on June 1. His position will be primarily research with some Extension appointment.

Abney is a native Georgian, growing up near Cochran in Bleckley County. He received his bachelorí s and masterí s degree from the University of Georgia and his doctorate degree from North Carolina State University in 2005. Abney has been assistant professor and Extension specialist in vegetable production at NCSU since that time.

Abney says the kinds of problems he addressed in vegetables are similar to those faced by peanut producers.

“Burrower bugs, threecornered alfalfa hoppers, thrips and caterpillars are just some of the pests affecting peanuts. Solutions to these problems will not come overnight, but I am looking forward to the challenge of developing effective insect control strategies and providing our growers with the most accurate and up-to-date pest management information,” he says.

Knowing that a great group of scientists are already at work on peanuts, Abney says he is excited to join the UGA Peanut Team. Welcome!

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