Ask Your PCA: What works for thrips in citrus and avocados?

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Issue Date: May 11, 2022

Chris Boisseranc Southwest Ag Consulting, Redlands

Chris Boisseranc

Citrus and avocado have problems with thrips, which damage the young, tender fruit and live in the flower. They will scar the early fruit. As the fruit develops and gets larger, the scar increases in size. If the fruit is damaged too extensively, it's sent to processing—the citrus to juice and the avocado to guacamole.

Whether it's citrus or avocado thrips, the damage is the same: It blemishes the fruit and makes it visibly unappealing. With significant damage, the fruit could have reduced size, too.

In citrus, thrips are a heat-driven pest. In avocado, it's a cool-weather pest. Avocados are native to the Mexican rainforest environment, which is why thrips damage avocado in cooler and more humidity-based areas.

Post-petal fall, thrips live in the calyx of the flower at the top of the fruit. Once the fruit begins to size, it becomes susceptible to damage from the thrips, and generally the pest is already in there, even before the susceptibility stage.

There are beneficial mites that help, but they usually can't control the population quick enough to prevent damage. Conventional sprays are the most predominant method for controlling thrips, and there are several materials available. There are organic chemicals available for control, too. To prevent bee injury, treatments don't start until after bloom is finished.

Two to three new materials have hit the market in the last few years, allowing conventional growers enough options to continually rotate and reduce the risk of resistance building. This provides growers with a good toolbox for managing this pest.

In drier and warmer regions, two applications may be necessary, particularly in the desert because the season is so long—from March to May. In the Central Valley, it's an April/May window, and for coastal avocado, it's also an April/May window for thrips.

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.