Symptoms and Control Methods of Jujube Fruit Borer
Jujube fruit borer, also known as jujube borer or Carposina niponensis, is a harmful insect that poses a significant threat to jujube trees, greatly affecting both yield and quality. Let's explore the symptoms and control methods of jujube fruit borer.
Symptoms of Jujube Fruit Borer Infestation
The larvae bore into the fruit, spinning webs on the surface before boring into it. They chew on the fruit skin underneath the webbing, then tunnel into the fruit. Soon, fruit gum flows out from the entry holes. Affected fruits develop abnormally, gradually turning purple-red on the surface and prematurely dropping. In severely affected jujube orchards, a large number of fruits drop when they are the size of beans. The remaining fruits, due to the damage caused by the larvae, accumulate as "red bean paste" inside and become inedible.
Jujube fruit borers have different generations each year in northern regions, mostly 2-3 generations. During the bud swelling period of jujube trees, overwintering larvae emerge from the soil. From the period of exposed buds and petals to before petal fall, overwintering larvae pupate. Late in the period after flower drop, adult moths can be observed. When the fruits are the size of green beans, it is the peak period for adult moths to lay eggs. When the fruits are the size of broad beans, it is the end period for adult moth oviposition. During the physiological fruit drop period, the first-generation larvae mature and begin to burrow into the soil. During the fruit harvesting period, the second-generation adult moths lay eggs. As the fruits ripen, the damage caused by jujube fruit borers intensifies.
Control Methods for Jujube Fruit Borer
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Deep plowing in orchards during winter: Deep plowing the orchard by 10 centimeters during winter helps reduce overwintering pupae. In winter, diseased branches and leaves can also be removed, and rough bark can be scraped off and burned. Spraying stone sulfur mixture on the trunk and ground can kill eggs in the tree crevices and soil.
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Mound soil to cover pupae: In late April, before jujube trees bloom, mounding soil around the trunk by 10 centimeters over a 60-70 centimeter radius and compacting it can suffocate emerging moths beneath the soil layer. After moth emergence, combined with loosening soil and weeding, the mounded soil should be removed.
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Chemical control: Before moth emergence or before the first-generation larvae leave the fruit, spread pesticide on the ground under the canopy; use 50% phoxim emulsion at a dilution of 300-500 times, with a usage rate of 0.25-0.5 kilograms per mu. During the adult moth occurrence period, spray 800 times diluted permethrin emulsion or 3000 times diluted fenvalerate emulsion, 3000-4000 times diluted cyhalothrin emulsion, or 4000-6000 times diluted deltamethrin emulsion on the trees.
Above are the introduction to the symptoms and control methods of jujube fruit borer. This pest occurs in both northern and southern regions and has a significant impact on the quality and yield of jujube fruits. Strengthening prevention and control measures is essential.
