The ingenious techniques that pests use to suck, cut or bore out plant juices are as varied as plant species themselves. Jerry Turney, plant pathologist with the Los Angeles Department of Agriculture, will talk to Garden Club members and guests about new pests and diseases for Southern California gardens on Monday, February 5 at 7:30 p.m. at the Woman’s Club, 901 Haverford. New pests are always coming into Southern California through a number of channels, Turney says. ‘They come on plant material, whether brought in legally or illegally.’ The newest star is the citrus leaf miner, which is a tiny moth, about 1/16 of an inch, that trashes citrus. The larvae get inside the leaf and chew from the inside out, leaving the leaves distorted and twisted. When the insect emerges it feasts on new growth and can stunt young plants. The fruit is not affected, but the systemic insecticides recommended for homeowners (as opposed to commercial use) to control the fly are restricted for ornamental uses only. Another clever pest that also affects citrus, and coral trees as well, is the Caribbean root weevil, which attacks the tree from both above and below the ground. The adults lay their eggs on the leaves, and the larvae lands on the ground, where it burrows down to spend a year underground feeding on the roots. The insect emerges and the adult weevil crawls up the trunk of the tree and feeds on the leaves. Turney, who holds a Ph.D., is a certified arborist serving as a licensed agricultural pest-control advisor with oversight for permission to use highly regulated pesticides. While pesticides are still used to control certain infestations, Turney says that the tide has turned from the old days, when ‘the adage was spray every Monday. Growers try to use as little as possible. They go out, check their crops and then decide to use pesticides in specific areas.’ Turney says that there is tremendous interest in using minimally toxic or non-toxic remedies to control pests such as oils and soaps, which smother the bugs. These are especially good in controlling sucking insects such as aphids and scale. Certain landscape plants are especially susceptible to pests, Turney says. ‘Ornamental pears are damaged by fire blight, and leaf spot is particularly difficult to control once it gets going.’ ‘One plant that I wouldn’t be planting right now is oleander, which is getting wiped out by leaf scorch, which is fatal.’ Guests are welcome to the free lecture.
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