Southern Green Stinkbug

Southern green stinkbug
Southern green stinkbug. Photo: Herb Pilcher, Bugwood.org

The southern green stinkbug, Nazara viridula, is a highly polyphagous feeder that attacks many important food crops, especially tomato.

Identification
In the past, stinkbugs were largely considered a minor problem whose numbers were kept in check by insecticide applications targeted at other pests. Stinkbugs have become a greater problem in recent years largely due to the move away from broad-spectrum insecticides to more pest specific biorational products. Stinkbugs can be recognized by their oval shape, five-segmented antennae, and malodorous scent.

The southern green stinkbug has piercing-sucking mouthparts. The mouth consists of a beak-like structure called the rostrum. Salivary fluid is pumped down the salivary duct and liquefied food is pumped up the food canal. All plant parts are attacked, but growing shoots and developing fruit are preferred. Damaged shoots usually wither, and may die.

The damage on fruit appears as hard brownish or black spots. Feeding punctures affect the edible qualities and lower its market value. Young fruit growth is retarded and often withers and drops from the plant. In addition to physical damage caused by southern green stinkbug feeding, mechanical transmission of tomato bacterial spot also may result. In tomato, adults and nymphs use piercing-sucking mouthparts to cause a lightened, and sometimes depressed, blotchy area under the fruit surface.

Survival And Spread
Stinkbugs are most prevalent during the periods of October through December and again in March through May. The southern green stinkbug can completes its life cycle in 65 to 70 days and may produce up to four generations per year in warmer areas.

The eggs are deposited in masses that range from 30 to 130 eggs per mass. The female oviposits on the undersurface of leaves in the upper portions of canopied crops and weeds. Weed hosts include beggerweed, rattlebox, Mexican clover, wild blackberry, and nutsedge. The eggs are barrel shaped and white to light yellow in color. Incubation time for the eggs is five days in the summer and two to three weeks in early spring and late fall.

The first instars aggregate by the empty eggs and do not feed. Feeding begins with the second instar. The second instar has black legs, head, thorax, and antennae. The third and fourth instars increase in size and gradually assume the overall greenish color of adults.

Management Methods
The Florida Tomato Scouting Guide sets the economic threshold for southern green stinkbug in tomato as one stinkbug per six plants. Stinkbugs, which were once routinely controlled with organophosphate and pyrethroid insecticides, may be pests that growers will need to manage more carefully in the future due to dramatic drop in the use of pyrethroid and organophosphate insecticides. Broad-spectrum insecticides such as Baythroid (cyfluthrin, Bayer CropScience), Brigade (bifenthrin, FMC Corp.), Danitol (fenpropathrin, Valent U.S.A.), Mustang (s-cyano, FMC Corp.), Pyrellin (pyrethrins, rotenone, Webb Wright Corp.), and Voliam Flexi (thiamethoxam, chlorantraniliprole, Syngenta) are labeled for use on tomato.