How to control the southern green stink bug? A few practical methods to teach you
The southern green stink bug (Nezara viridula) occurs in sweet citrus-producing areas across China. Besides harming citrus, it also damages rice, corn, peanuts, cotton, beans, cruciferous vegetables, rapeseed, sesame, eggplant, peppers, potatoes, peaches, plums, pears, apples, and more. Both adults and nymphs damage tobacco plants by piercing and sucking the sap from tender top leaves and stems. Let us take a look below at how to control the southern green stink bug!
Damage characteristics of the southern green stink bug
The larvae of the southern green stink bug overwinter among the leaves of conifers such as Japanese cedar and cypress, and evergreen trees such as camellia and mandarin orange, as well as in palm fiber, rice straw, and on the inner side of roofs. By April they move to wheat and cruciferous vegetables. The first egg-laying plants are mainly potatoes. It has 3 generations per year. When food plants and temperatures are suitable, the larvae develop extremely quickly, and it can have 4 generations per year. Both adults and nymphs damage tobacco plants by piercing and sucking the sap from tender top leaves and stems. Water-soaked wilting often appears first at the pierced and sucked sites on the leaves, followed by drying up. In severe cases, the upper leaves or the top shoot of the tobacco plant wilt.
Occurrence patterns of the southern green stink bug
The southern green stink bug overwinters as adults on various host plants or in sheltered, leeward places. In Yangcun, Guangdong, Guilin, Guangxi, and Guizhou, it has 3 generations per year. In citrus orchards, adult activity is first seen in early April. Eggs are laid on leaf surfaces, 30-50 arranged in a mass. Newly hatched nymphs gather around the egg shells, and after the 2nd instar they disperse to feed. After about 50-65 days they become adults. First-generation adults appear in June-July, second-generation adults appear in August-September, and third-generation adults appear in October-November. Major outbreaks in citrus orchards each year are related to adults that damaged rice paddies after the summer and autumn rice harvests flying into citrus orchards. At this time large numbers of southern green stink bugs gather in citrus orchards to suck fruit juice, greatly affecting fresh fruit quality and reducing commercial value.
How to control the southern green stink bug?
1. Reduce insect sources: During winter and spring, combine manure accumulation with clearing weeds near field edges to reduce overwintering insect sources.
2. Manual capture and killing: Take advantage of the adults' poor flying activity in the morning and evening to carry out manual capture and killing.
3. Chemical control: Apply pesticides when nymphs are at the peak outbreak stage and are still clustered near the egg shells before dispersing. You may choose 90% trichlorfon 700x solution, 80% dichlorvos 800x solution, 50% fenitrothion emulsifiable concentrate 1000-1500x solution, 40% dimethoate 800-1000x solution, 25% phosmet 700x solution, or pyrethroid pesticides 3000-4000x solution for spraying.