-

Greenhouse studies were conducted to determine the effects of
natural and simulated cereal leaf beetle Ouema melanopus (L.)
defoliation on the yield and growth components of Potomac wheat.Five larval densities (0,3,6,12, and 24 larvae per set of 6 plants)were
established at three stages of plant maturity (boot,50/.soft- dough) In other studies, five defoliation levels, equivalent to the damage
caused by the above larval densities, were simulated at the same
maturity stages using two different defoliation methods (sandpaper and scissor)
The general trend was a reduction in the number, size, and weight of seed with an increase in leaf area removed or larval density.
Reductions in the yield components were obviously associated with the
loss of stored and synthesized materials in the leaves. The most
critical time for damage was when the plants were beginning to head until flowering.Diffeential yield responses relative to growth stage were apparently associated with the amount of photosynthates being
translocated to the seed head prior to the time of defoliation.
Both methods of simulated defoliation had little effect on the growth components (stem and head length, dry weight of seeds and chaff) of the wheat plant.
The methods to simulate defoliation are compared and the application of the results to the actual field situation is discussed.