I. Symptoms of Spider Mite Damage
The spider mite mainly damages eggplants, peppers, and melons. Adult mites, nymphs, and larvae mainly gather on the undersides of leaves to suck sap. In the early stage, sporadic spots of green color loss appear on the leaf surface, gradually turning gray-white. When the damage is severe, the leaves become scorched, resembling a burnt appearance, causing early leaf drop and premature plant aging. The mites can also damage fruits, resulting in grayish, rough fruit skins that become shriveled, reducing fruit quality. Affected plants have a shortened fruiting period, significantly impacting yield and quality.
II. Rules of Spider Mite Damage
The mites undergo 10-20 generations each year. In the northern regions, female mites overwinter in weeds and soil cracks, while in the south, eggs, adult mites, nymphs, and larvae can overwinter in host plants or weeds. Eggs are mostly laid on the undersides of leaves. They can reproduce sexually or parthenogenetically. High temperatures and low humidity favor the occurrence of spider mites, while rainfall inhibits their occurrence. The number of mites is also influenced by environmental conditions, with heavier infestations occurring in vegetable fields adjacent to cotton, legumes, and maize, as well as fields with abundant weeds along the edges.
III. Control Measures for Spider Mites on Solanaceous Vegetables
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Clearing Weeds: Remove weeds, dead branches, and fallen leaves from field edges, roadsides, and ditches to eliminate overwintering sources. During dry weather, pay attention to irrigation to increase field humidity.
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Using Natural Enemies: Natural enemies of spider mites include predatory mites, ladybugs, lacewings, minute pirate bugs, and damsel bugs. When the density of spider mites is low, release predatory mites at a ratio of 3:1 (spider mites to predatory mites). Starting from mid-June, release them once every 10 days, for a total of 2-3 releases.
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Chemical Control: At the onset of spider mite infestation, chemical control can be implemented using methods similar to those used for controlling tea mites.
Above are the common spider mite damages found on solanaceous vegetables and their control measures. It's essential to remain vigilant and take preventive measures.
