News Stories

A new pest is introduced into California every 60 days on average, according to California Department of Food and Agriculture statistics. As new pests invade and attack the state's ornamental and agricultural crops, the University of California's Integrated Pest Management Project continues to develop new strategies to battle them. For the past 20 years, the UC IPM Project has been designing pest-control programs that are economically and environmentally beneficial. IPM advisors have helped growers reduce the pesticide load in the environment; enhance the predictability and effectiveness of pest-control techniques; and increase use of natural pest controls.

The November-December issue of California Agriculture features examples of the UC IPM Project's recent achievements.

Eucalyptus pests. Since the detection of the first introduced pest of eucalyptus in 1985, the rate of discovery of a new eucalyptus-feeding insect has approached one per year. UC scientists describe the IPM methods they are using to stem the spread of the recently introduced red gum lerp psyllid, eucalyptus tortoise beetle and a longhorned borer species called Phoracantha recurva. They are monitoring the pests, establishing natural enemies and employing different cultural practices to make trees less attractive to the herbivorous insects.

Dormant sprays. A survey of pesticide use reports from 1992 to 1998 shows a decline in organophosphate use in dormant almond and stone fruit orchards in California. Instead of applying an organophosphate insecticide dormant-season spray, almond growers can monitor and treat only when pests are present. For the peach twig borer, one alternative is a bloomtime spray of the microbial agent Bacillus thuringiensis.

Alternative weed-control methods. To help control yellow starthistle, UC scientists have developed programs integrating mowing, grazing, clover plantings, insects, prescribed burning and selective applications of herbicides. Combinations of chemical, mechanical, cultural and biological techniques can be used in strategies for site-specific control of yellow starthistle. For weed control in alfalfa crops, planting grasses into older alfalfa stands reduces weeds and suppresses alfalfa weevil populations.

Fumigation without methyl bromide. Methyl bromide is scheduled to be phased out by 2005. In their search for methyl bromide replacements, UC scientists have found that solarization and biofumigation can disinfest soils of pests and pathogens in some cases. By covering moistened soil with clear polyethylene film, they used the hot summer sun to "cook" the weeds, insects, nematodes, fungi and bacteria in the top layers of soil. Other studies have shown that an effective fumigation method combines solarization with cabbage or broccoli residues or composted animal manures. The heat releases biotoxic volatile compounds from the residues that kill disease-causing pathogens.

California Agriculture is the University of California's peer-reviewed journal of research in agricultural, human and natural resources. For a free subscription, call (510) 987-0044 or e-mail us at calag@ucop.edu. Visit California Agriculture on the Internet at our redesigned site http://danr.ucop.edu/calag.