The latest Arizona Vegetable Integrated Pest Management Update from the University of Arizona (UA) Cooperative Extension in Yuma, Ariz., released Aug. 24, 2011.

Bagrada bug control on desert cole crops

By John Palumbo, UA Research Scientist and Extension Specialist

Compared to last year, Bagrada bug adult numbers have been relatively light on early broccoli plantings and cauliflower/cabbage transplanted fields in the Yuma and Dome valleys in southwestern Arizona.

Over the summer there were few reports of Bagrada bug adults found in cotton, alfalfa, sudangrass, and other seasonal crops relative to last summer.

Does this suggest that Bagrada numbers will continue to be light once we get into September and acreage begins to increase? It is possible, but I would not bet on it just yet. Remember, it was not until around mid-September last year when it seemed like the clouds opened up and Bagrada bugs dropped from the sky.

Pest control advisors (PCAs) and growers should not become complacent just because they are not finding any Bagrada yet. Rather, it would be wise to assume the bug will eventually show up in some intensity and to prepare for the insect accordingly.

Preliminary research conducted over the past year suggests that direct-seeded and transplanted crops are most susceptible to Bagrada bug infestations during stand establishment.

Research to date also suggests that heavy Bagrada infestation control with insecticides is the most economically viable option to protecting stands and preventing significant yield losses. This includes chemigation with pyrethroids, and using contact insecticides (pyrethroids, Lannate, Lorsban) once plants emerge and the irrigation pipe is pulled.

After stands are established and plant size increases up to the 3-4 leaf stage, or on growing transplants, PCAs may consider alternating to dinotefuron (Venom/Scorpion) for protecting plants from Bagrada feeding. This neonicotinoid will also provide knockdown of adult whiteflies and nymphs.

More information on Bagrada bug control can be found in these research reports conducted in a 2010 field trial and a 2011 greenhouse trial.

Contact Palumbo: (928) 928-782-3836 or jpalumbo@ag.arizona.edu.