Detailed Explanation of Control Techniques for the Four Major Pests of Jujube Trees

I. Control of the Jujube Inchworm

The jujube inchworm is also called the jujube looper. Its larvae damage tender buds, leaves and flower buds, and in severe cases often cause a second flush of sprouting. Control methods:

1. Biological control. Protecting natural enemies is the main channel of biological control. The ichneumon wasp Tumidifemoralis ichneumon, the silkworm tachinid fly and the colorful broad-fronted tachinid fly use jujube inchworm larvae as hosts, with a parasitism rate of 30%-50% on mature larvae. Attention should be paid to protecting them.

2. Chemical control. Before the larvae reach the 3rd instar, spray 1500x 25% chlorbenzuron No. 3 or 2000x 20% tebufenozide solution 1-2 times, or spray 2000x 20% fenvalerate emulsifiable concentrate, 3000x 2.5% lambda-cyhalothrin emulsifiable concentrate, etc., which can effectively eliminate the damage caused by jujube inchworm larvae.

II. Control of the Peach Fruit Borer

The peach fruit borer is also called the fruit borer. It mainly damages jujube fruits with its larvae; the larvae bore and feed around the pit inside the jujube fruit, leaving frass inside the fruit, appearing like “red bean paste filling”. Early damage causes fruit drop, and later damage causes infested fruits, seriously affecting the yield and quality of red jujubes. Control methods:

1. Biological control. There are several species of parasitic wasps of the peach fruit borer, among which the peach fruit braconid wasp and the Chinese toothed-legged ichneumon wasp have relatively high parasitism rates. The peach fruit braconid wasp lays its eggs inside peach fruit borer eggs, and its larvae parasitize inside peach fruit borer larvae; after the overwintering larvae emerge from the soil and spin cocoons, they are completely consumed. Therefore, peach fruit borer parasitic wasps can be released during the peak occurrence period of the overwintering-generation adults. During the initial hatching period of the larvae, spray bacterial pesticide (BT emulsion) to cause the peach fruit borer to become diseased and die. Peach fruit borer sex pheromone lures can also be used to trap and kill adults during the occurrence period of the overwintering generation.

2. Chemical control. Applying poisoned soil: mix 2 kg of 15% chlorpyrifos granules or 500 g of 50% phoxim emulsifiable concentrate per mu thoroughly with 15-25 kg of fine soil, evenly spread it on the ground under the tree trunk, and use a hand rake to mix the poisoned soil with the soil and level it. Chlorpyrifos only needs to be applied once; phoxim should be applied 2-3 times consecutively. Ground spraying: use 300-500x 48% chlorpyrifos emulsifiable concentrate, spray the ground thoroughly before the overwintering larvae emerge from the soil, and rake the surface loose. Tree spraying: the suitable control period is the initial hatching period of the larvae; spray 1000-1500x 48% chlorpyrifos emulsifiable concentrate, which has a strong contact-killing effect on eggs and newly hatched larvae; you can also spray 2000x 20% fenvalerate emulsifiable concentrate, or 1500x 10% cypermethrin emulsifiable concentrate. Spray once more after one week to achieve good control results.

III. Control of the Jujube Leaf Roller

The scientific name of the jujube leaf roller is the jujube sickle-winged small tortricid moth. During the bud-break and leaf-unfolding period, it damages tender buds and tender leaves, causing a second flush of sprouting; during the flowering period, it bites off flower stalks and damages flower buds; during the young fruit period, it bores into and feeds on young fruits, causing fruit drop; during the fruit enlargement period, the larvae spin silk to stick jujube leaves and fruits together and bore into and feed on the fruits, causing a large number of infested fruits. Control methods:

1. Biological control. During the growth period of jujube trees, especially during the flowering and fruiting periods, in order to address pesticide damage and residues and to help protect natural enemies and pollinating insects, this can be solved by releasing Trichogramma wasps and using biological pesticides. During the 2nd and 3rd generation egg periods of the jujube leaf roller, release 3000-5000 pine caterpillar Trichogramma wasps per tree, with a parasitism rate of about 85%. Spray 100-200x biological pesticides Bacillus thuringiensis and Bacillus sphaericus, with a larval control effect reaching 70%-90%.

2. Chemical control. When the tender shoots of jujube trees grow to about 3 cm (that is, the peak hatching period of the 1st-generation larvae), this is the key period for pesticide control. Use 4000x 2.5% deltamethrin emulsifiable concentrate, 3000x 20% fenvalerate emulsifiable concentrate, etc., all of which are acceptable.

IV. Control of Red Spider Mites

They mainly damage jujube leaves and tender parts; in severe cases the leaves turn yellow and dry, causing early defoliation and fruit drop. They generally occur easily under high temperature and drought. Control methods:

1. Biological control. There are many kinds of natural enemies of red spider mites, mainly including the Chinese green lacewing, mite-eating ladybeetles and predatory mites, among which the Chinese green lacewing has a relatively large population and a relatively large predation capacity on jujube red spider mites. Protecting and increasing the number of natural enemies can enhance their control effect on jujube red spider mite populations.

2. Chemical control. Using 4000-5000x clofentezine solution, 2000x 15% pyridaben emulsifiable concentrate, 6000-8000x 1.8% abamectin emulsifiable concentrate, etc., can all achieve ideal control results.