A Detailed Explanation of the Occurrence Patterns and Control Methods of the Jujube Leafroller

The jujube leafroller belongs to the order Lepidoptera, family Tortricidae. Common names include leaf-tying worm, leaf-sticking worm, leafroller, and so on. It occurs and causes damage to varying degrees in most jujube-growing areas nationwide, and is one of the major pests of jujube trees.

I. Damage characteristics

The jujube leafroller uses its larvae to spin silk and damage buds, leaves, flower buds, flowers, and fruits. Especially the third-generation larvae, which are in the fruit-coloring period, often glue jujube leaves and jujube fruits together with thin silk, and within this shelter gnaw at the jujube skin and flesh at the fruit stalk, causing a large number of fallen and rotten fruits.

II. Life habits

In the Shandong and Hebei areas, three generations can occur per year. The overwintering generation begins to emerge and lay eggs in mid-to-late March, and the first-generation larvae hatch in early-to-mid April and begin to damage jujube buds. The peak damage period of the second-generation larvae is in early-to-mid June and can continue into early July (the flowering and fruit-setting period). The peak damage period of the third-generation larvae is from late August to early September and can continue into mid-September. After that, the mature larvae gradually move to cracks in rough bark, where they spin cocoons, pupate, and overwinter. The peak hatching and damage periods of the second- and third-generation larvae are irregular, with generation overlap, which brings considerable difficulty to control. Larvae of each generation all spin silk, joining flowers and leaves, leaves and fruit clusters, and leaves and fruits, hiding within to cause damage, resulting in fallen flowers, fallen fruits, and rotten fruits.

III. Control methods

In addition to physical and biological measures such as scraping bark in spring to eliminate pupae, using insect-killing lamps to trap and kill adults, releasing Trichogramma in jujube orchards, and spraying BT biological insecticides, the key is to carry out chemical control well.

In winter jujube orchards, the first-generation larvae can be controlled together with pests such as the green plant bug, with no need for additional control. Most second-generation larvae can also be controlled during the control of pests such as red spider mites, but because the second and third generations have the characteristic of generation overlap, pesticide should be sprayed once in late July or early August. Particularly critical is the occurrence and damage of the third generation; from late August to early September, pesticide should be sprayed 2-3 times consecutively to achieve thorough control, otherwise jujube fruits will suffer heavy losses.

Pesticide options include: Wodeying 1200 times, Qigong 1500 times, Kangchong Sumie 1500 times, Jiagao or JIagong (emamectin benzoate + beta-cypermethrin or Kung Fu) 1500 times.