14 MISCELLANEOUS PUBLICATION 1348, U.S. DEPARTMENT OF AGRICULTURE 
Forage reduction (kilograms per hectare) 
at 1 grasshopper per square meter 
Camnula Amphitnorus 
pellucida feeding on coloradus feeding on 
Instar Poa pratensis Stipa comata 
1953, 1st-5th-incl. 5.85 
1954: 
Ist 118 _ 
2d .362 0.375 
3d 853 .629 
4th 2.216 1.733 
Sth 5-115 3.926 
Adult 7.110 
11.475 
Thus, during the nymphal life of C. pellucida, the 
yield was reduced by 5.8 kg/ha for each grasshop- 
per per square meter and 3.9 kg/ha for A. colo- 
radus. Putnam stated that young C. pellucida 
adults reduced the yield by about 95 mg per grass- 
hopper per day and destroyed as much in 5 days as 
in their whole peziod of nymphal growth. Each 
young adult of A. coloradus reduced the yield by 
about 53 mg per day. He concluded that 24 adults 
per square meter of either species could take the 
entire available yield if 50 percent of the available 
forage can be safely harvested. Putnam (1962) sug- 
gested that the appropriate stage at which to con- 
trol such a population would be the third instar, on 
the assumption that recruitment by this time is 
negligible and that the maximum rate of damage 
occurs during the adult stage. 
Randell (1970), who developed a model based on 
Putnam’s findings with C. pellucida, suggested that 
the timing of control measures may be more critical 
because according to his model the maximum rate 
of damage occurs when the population is in the 
fourth instar when numbers and appetite combine 
to yield the highest feeding rate. His model also 
suggested that the greater numbers of young 
nymphs contributed more than 1s of the total dam- 
age as opposed to '/* to 7 suggested by Putnam. 
Randell (1970) also determined for Melanoplus san- 
guinipes a value of 356 mg as the dry weight of food 
required per individual from hatching to the adult 
stage. When used in this model, this figure sug- 
gested that a total consumption of 394 kg/ha (dry 
wt) is a valid estimate of the total consumption of a 
population of 24 grasshoppers per square meter at 
the adult stage experiencing normal field mortality. 
Misra and Putnam (1966) carried out laboratory 
and field experiments with Camnula pellucida to 
compare food consumption between laboratory and 
field reared grasshoppers. They determined the 
dry weight of Poa pratensis required to rear grass- 
hoppers from hatching to the adult stage as 321 mg 
per insect in the laboratory and 476 mg per insect in 
the field. This is equivalent to a consumption of 3.8 
and 5.7 kg of forage per hectare by an infestation of 
one grasshopper per square meter during the 
nymphal life. A loss of 38.7 mg per day was deter- 
mined for each adult reared in the laboratory and 
96.1 mg per day for those reared in the field. 
Pruess (1970) compared ingestion of bluestem 
and ragweed between populations of adult Ageneo- 
tettix deorum from Nebraska and Kansas. He found 
that in 6 days of feeding the Nebraska grasshoppers 
ingested 81.4 mg per grasshopper and the Kansas 
grasshoppers, 85.1 mg per grasshopper. He con- 
cluded that plants from Kansas were more digesti- 
ble for both grasshopper populations; however, 
ragweed from neither source was acceptable nor 
utilized by either grasshopper population. 
Parker (1930) was probably the first worker to 
determine food consumption for Melanoplus san- 
guinipes. He fed wandering-Jew (Zebrina spp.) to 
nymphs held at different temperatures in the labo- 
ratory with the following results: 
Food consumption (mg) by 10 nymphs (during 
nymphal stage) at constant and alternating tem- 
peratures 
Constant Alternating ' 
Temperature (°C) temperature temperature 
27 6,796 4,700 
32 6,959 5,061 
37 TATS 4,639 
116 hr at 12° Cand 8 hr at 27°, 32°, or 37° C. 
Parker concluded that there was a 24-percent 
reduction in food consumed and a 30-percent reduc- 
tion in the time spent in the nymphal stage by those 
grasshoppers reared under alternating tempera- 
tures. The author also found that 10 adults during a 
period of 20 days consumed 11,587 mg at 37° C, 
8,929 mg at 32°, and 4,836 mg at 27°. He stated 
that, generally, immediately after the adult stage is 
reached, daily food consumption increased rapidly 
and reached its maximum in about a week, at which 
time it may be from 50 to 75 percent greater than 
during the last nymphal instar. From 21° to 27° C, 
feeding activity is greatest and will decrease 
rapidly at both above and below these tempera- 
tures. Grasshopper damage should, therefore, be 
