BLACKFACED LEAFHOPPER: Graminella nigrifrons, Cicadellidae

ADULT: These small (1/8 in. long), narrow leafhoppers exhibit tremendous color and pattern variations throughout their North American range. Body color ranges from pale yellow to dark green. On those with medium to dark bodies, the area above the mouthparts and between the compound eyes have six to nine rows of transverse blue to black bars extending toward the center of the face, and six longitudinal bars on top of first thoracic segment. Light and dark individuals all have an arc of four spots on the rounded front margin of the vertex between the compound eyes. Antennae are thin and as long as the first pair of legs.

EGG: Eggs are deposited in leaf blades. The tips of the eggs protrude slightly above the leaf surface a day or two before nymphs emerge with eye spots developing in 6 to 9 d. The egg stage lasts 12 to 14 d at 70 to 75 degrees F.

NYMPH: They are very small, wingless, pale colored, and require an average of 34 d. to complete development (4 to 6 instars) to adult at 70 to 75 degrees F.  There is no pupal stage in cicadellids.

GENERATION TIME: 31 to 38 d at 70 to 75 degrees F

DAMAGE: Together with the aster leafhopper, they account for the majority of leafhoppers collected in U.S. corn. In the Everglades Agricultural Area they are most common in August and September. They transmit the semipersistant maize chlorotic dwarf virus and the persistent diseases maize rayado fino maya virus (MRFM), corn stunt spiroplasma (CSS) and maize bushy stunt phytoplasma (MBSP). These diseases are rare, but are more common in south Florida, where local outbreaks causing economic losses have occurred.

CONTROL: Leafhoppers rarely reach densities in Florida corn that require insecticides to prevent feeding damage.  Parasitic wasps attack leafhopper eggs, and spiders are important predators of nymphs and adults. The biggest concern for damage is associated with virus transmission.  Research has shown that pesticides are an inefficient means to prevent primary virus transmission, but some success is known for persistent viruses. Virus diseases are probably held largely in check bylack of virus reservoirs. Varietal resistance in corn to insect-transmitted virus is being addressed by several plant breeders and has the greatest potential for disease prevention. Several insecticides currently used to control fall armyworm also kill leafhoppers. Pesticides are available for foliar applications. Formulations, rates, and pre-harvest intervals of insecticides for blackfaced leafhopper control are listed below for sweet corn (Table 1) and field corn (Table 2).

Table 1.  Chemical control of leafhoppers in sweet corn
Insecticide, formulation Rate/acre Min. days to harvest Application notes
carbaryl (Sevin, Sevin XLR Plus) 4 F, 4 EC 1 - 2 qt 2 ears; 48 forage; 14**  
carbaryl (Sevin) 80 WSP 1.25 - 2.5 lb 2 ears; 48 fodder; 14**  
oxydemetonmethyl (MetaSystox-R) 2 EC 1.5 - 2 pt 7 - 1 app., 21 - 2 app.  
permethrin (Pounce) 25 WP 6.4 - 12.8 oz 1  
permethrin (Pounce) 3.2 EC 4 - 8 fl oz 1  
permethrin (Pounce WSB) 24.7% WSB 6.4 - 12.8 oz 1  
pyrethrins + piperonyl butoxide (Pyrenone) 66% L (EC) 2 - 12 fl oz 0  
pyrethrins + rotenone (Pyrellin) EC 1 - 2 pt 12 hr  
soap, insecticidal (M-Pede) 49% EC 2 gal/100 gal water 0  
**harvest or grazing of forage or silage


Table 2.  Chemical control of leafhoppers in field corn
Insecticide, formulation Rate/acre Min. days to harvest Application notes
carbaryl (Sevin, Sevin XLR Plus) 4 F, 4 EC 1 - 2 qt 48 fodder, grain; 14**  
carbaryl (Sevin) 80 WSP 1.25 - 2.5 lb 48 fodder, grain; 14**  
disulfoton (Di-Syston 8) 8 EC 1.2 fl oz / 1000 row-ft 28 banded at plant or injected post-plant, not in-furrow
pyrethrins + rotenone (Pyrellin) EC 1 - 2 pt 12 hr  
**harvest or grazing of forage or silage