BROWN STINK BUG: Euschistus servus, Pentatomidae

ADULT: Brown, shield-shaped bugs with yellow or light green under surface. The lateral edges of the pronotum point outward in broad blunt points. Adults reach 1/2 to 2/3 in. long.

EGG: The barrel-shaped, pale yellow (becoming tan), 1/16 in. tall eggs are deposited under leaves and arranged closely in a series of rows and in groups of 8 to 40 (average 18). The eggs are not deposited as closely as those of southern green stink bugs. Nymphs emerge in 5 to 7 d.  at 73 degrees F.

NYMPH: All five nymphal instars are yellow to tan with a brown pronotum and reddish to brown spots that run down the back of the abdomen. Aggregative and feeding behaviors are similar to southern green stink bugs. Variegated brown wingpads extend back from the pronotum on the back in the fifth instar. Nymphs complete development in an average of 39 d at 73 degrees F.  There is no pupal stage in pentatomids.

GENERATION TIME: Average of 45 d at 73 degrees F.

DAMAGE: Stink bugs are greater pests in central and northern Florida than in south Florida, where most production is completed before these stink bugs become common. Stink bugs feed by puncturing plant tissue and sucking out plant fluids. Feeding on seedlings results in a high percentage of stunting, plant mortality (20%), tillering (greater than 50%) and subsequent reductions in yield.  Part of the yield loss associated with poor pollination is caused by delays in silking in tillered plants.  Ears are also attacked and kernels punctured through the husks causing them to become sunken or to pop open. Ear feeding can also lead to a higher incidence of corn smut. Injured kernels become infected with fungus. Several other brown-colored stink bugs in Florida have the edge of their pronotums protruding into more or less sharp points, including the narrower rice stink bugs. Many of these are important predators of caterpillars and beetles on corn.

CONTROL: Populations can be clumped in fields due to their aggregative nature during early instars.  Spot or edge treatments with pesticides may be enough to prevent economic damage.  Treatment thresholds are available for field corn during ear stage.  These suggest application of foliar sprays when density of nymphs greater than 1/4 in. long reaches one per five plants during early silking through milk stage.  Higher densities of one per plant are suggested for the period from early milk through hard dough stage.  Due to consumer expectations and shelf life concerns, thresholds would be lower in sweet corn to prevent economic losses.  Pesticides are available for post-emergence foliar application.  Formulations, rates, and pre-harvest intervals of insecticides labeled for stink bug control in Florida are listed below for sweet corn (Table 1) and field corn (Table 2).

Table 1.  Chemical control of stink bugs in sweet corn
Insecticide, formulation Rate/acre Min. days to harvest Application notes
cyhalothrin (Karate, Warrior) 1 EC 2.56 - 3.84 fl oz 1  
methyl parathion (Penncap-M) 2 EC 1 - 3 pt 3 ears; 12 forage, grazing  
pyrethrin + piperonyl butoxide (Pyrenone) 66 % L (EC) 2 - 12 fl oz 0  
pyrethrins + rotenone (Pyrellin) EC 1 - 2 pt 12 hr  

Table 2.  Chemical control of stink bugs in field corn
Insecticide, formulation Rate/acre Min. days to harvest Application notes
cyhalothrin (Karate, Warrior), 1 EC 2.56 - 3.84 fl oz 21  
ethyl parathion (Parathion) 8 EC 0.5 pt 12  
methyl parathion (Penncap - M) 2EC 1 - 3 pt 12  
pyrethrins + rotenone (Pyrellin) EC 1 - 2 pt 12 hr