A Detailed Explanation of the Damage Characteristics and Control Methods of the Jujube Geometer Moth

I. What Are the Damage Characteristics and Living Habits of the Jujube Geometer Moth?

The jujube geometer moth, also known as the bow-waisted worm, the top-door eater, or the jujube looper. When the larvae crawl, they stretch and contract, hence the name "jujube looper." It is one of the most important insect pests of jujube trees. It is distributed throughout all major jujube-growing regions in China, with the most severe damage occurring in the jujube regions of Hebei, Shandong, Henan and Shanxi provinces. Its larvae are highly voracious, damaging all green tissues of jujube trees, including tender buds, leaves, flower buds, bearing shoots and new branch tips. In severe outbreaks, they can eat all the jujube leaves or buds bare, causing severe yield reduction or total crop failure.

In North China, the jujube geometer moth has one generation per year, emerging in March to April each year. Male adults have wings and can fly; female adults are wingless and, after emergence, first hide in the weeds under the trees, then at dusk or night crawl up the trees to mate with the males, after which they lay eggs on tender buds, in bark crevices and other such sites. The eggs hatch around mid-April. The newly hatched larvae first gather at the tips of the branches to damage the tender buds, which is why people in jujube-growing areas call it pupation. The larvae crawl quickly and, when startled, have the habit of spinning silk and dropping down from the tree, allowing them to spread and move to surrounding areas. So when the leaves of one jujube tree are eaten bare by them, they can spin silk and drop to the ground to move to other jujube trees.

In addition, the geometer moths that damage jujube trees also include the jujube silver-gray geometer moth, the black locust geometer moth, the mulberry wing-folded geometer moth and the wild jujube geometer moth. Their living habits and damage patterns are roughly the same as those of the jujube geometer moth.

II. What Are the Comprehensive Control Measures for the Jujube Geometer Moth?

To carry out comprehensive control of the jujube geometer moth, the following main measures can be taken:

1. Dig out overwintering pupae and catch larvae. In spring (before mid-March), within a 100 cm radius around the tree trunk, turn and dig the soil layer to dig out and destroy the overwintering pupae. You can also pick out the pupae when digging the tree basin in early winter or early spring. You can also take advantage of the larvae's habit of playing dead and falling to the ground when startled by shaking the tree during the larval damage period to dislodge the larvae and kill them on the spot.

2. Block female moths from climbing the trees and collect eggs. Since female moths cannot fly, in mid-to-late March you can wrap plastic film or a paper skirt around the trunk to prevent female moths from climbing up to mate and lay eggs, and catch the moths tree by tree every morning or evening. Whether wrapping a paper skirt or plastic film around the trunk, you must nail the seam tightly with no gaps, so that female moths cannot take advantage of a gap to climb up. Because the trunk is wrapped, female moths cannot climb up and instead mostly gather to lay eggs in bark crevices beneath the skirt. Therefore, you can periodically pry open the coarse bark and scrape off the eggs, or tie two loops of straw rope beneath the skirt to attract female moths to lay eggs, replacing the straw rope about every 10 days and burning it. You can also bury the lower part of the plastic skirt into the soil at the base of the trunk to directly block moths from climbing up, and catch moths on the ground around the tree every morning or evening. Or directly scrape the trunk and apply a 10 cm wide ring of insect glue. If there is no insect glue, machine oil can be applied instead. This sticks the female moths directly to the trunk, where they can then be killed.

3. Chemical control. According to the characteristics and damage patterns of the jujube geometer moth, chemical control can be applied in two rounds. For the first application, when the jujube buds have grown to about 3 cm long (early May), spray 50% dichlorvos or 75% phoxim at 800-1000 times dilution, or spray 50% parathion at 1000-1500 times dilution. For the second application, when the jujube buds have grown to 5-8 cm (mid-May), spray 20% fenpropathrin-malathion emulsifiable concentrate at 4000 times dilution, or 35% insecticidal phosphorus emulsifiable concentrate at 1000 times dilution, or 35% tetramethyl thiocyclophosphamide emulsifiable concentrate at 1500 times dilution, or 50% monocrotophos at 1000 times dilution, fenpropathrin and fenvalerate at 3000 times dilution, 2.5% deltamethrin at 1500 times dilution, or 20% fenvalerate at 6000 times dilution, etc.