Time to Monitor What's Bugging Almonds

As we say good-bye to March and another rain-starved month featuring above average temperatures, almond growers are telling us that something has been bugging them lately.

Leaffooted plant bug.

Leaffooted plant bugs are becoming troublesome and could cause nuts to fall off the trees in the coming month or the kernels to shrivel by harvest time, says field scout Jenna Horine.

 

Lately, Jenna has been fielding calls from farmers detailing the pest problem, especially in orchards on the warmer west side, where the crop tends to develop faster. The pests are looking for food and emerging locations such as neighboring fence lines, riparian areas and fields that have been fallow for years.

Here's an egg mass from the leaffooted plant bug

 The time is ripe for leaffooted bugs to strike now and cause lots of damage. Stink bugs cause similar problems later in the spring. These pests will penetrate the soft nut and suck out the juicy center of the developing kernel. You can tell they have struck because of the gummy residue left on the outside of the hull.

Sticky substance on the almond hull.

Pest experts say the leaffooted bug could be a problem this season because of high populations spotted last fall and a large survival rate because of the mild winter. Normally, the cold winter temperatures act and an egg parasite act as a natural control by killing off the overwintering leaffooted bug. 

Bug damage inside almond.

From now through May is the prime time to conduct weekly monitoring for the pest. Growers can do this by using a long pole to knock around branches on the upper canopy and watch or listen for the pests to fly around. A clear to light amber sticky substance, called gummosis, found on the hull is a sure sign of their presence – although that means the damage has occurred already. Leaffooted bug damage occurs in March and April while stink bug damage is more common in May and June.

 UC IPM says growers can make sure gummosis is caused by pests by cutting a cross section of the damaged area and then looking for a puncture mark from the bug’s mouthparts. Growers should double check with their pest control advisors when considering treatment and also consider reduced risk materials to protect good bugs that keep almond pests such as spider mites under control during the season.