CORN LEAFHOPPER: Dalbulus maidis, Cicadellidae

ADULT: A small (5/32 in. long), narrow, pale yellow to greenish-yellow leafhopper with a black spot above each ocellus on the crown of the head between the compound eyes.  Crown of head is smooth.  Rear margin of first thoracic segment deeply indented to form an indented "V" shape.  Rear tibia are held forward under femora in preparation for jumping. Females live 26 to 51 d and produce an average of 151 eggs.

EGG: They are deposited into leaf tissue. Nymphs emerge in 2.5 d at 80 and 90 degrees F.

NYMPH: They look similar to adults, but without wings.  Corn leafhoppers complete development in 10 d at 80 and 90 degrees F.  There is no pupal stage in cicadellids.

GENERATION TIME: Corn leafhoppers complete development in 27, 22.5 and 14 d at 70, 75 and 80 to 90 degrees F, respectively.

DAMAGE: These leafhoppers are found throughout Florida. They transmit maize rayado fino maya virus (MRFM), and the diseases corn stunt spiroplasma (CSS) and maize bushy stunt phytoplasma (MBSP). These diseases 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 by lack 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 corn 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