Quantifying Key Variables of Damage to Wheat and Barley by Syringopais Temperatella (Lepidoptera: Scythrididae)

Abstract

Wheat and barley are the principal food crops for millions of people in the predominantly mixed crop-livestock farming systems. The cereal leafminer, Syringopais temperatella (Lepidoptera, Scythrididae) is a major biotic constraint to wheat and barley production in Jordan and the region. Three variables of yield components were used to quantify the loss of wheat and barley including the grain yield, straw dry mass and leaf area consumed. Forty-two (in the field experiment) and one hundred eighteen (in the laboratory experiment) accessions of wheat and barley were used to access the average damage; representing different levels of susceptibility to S. temperatella. Equations of three negative correlations of percentage of infestation versus both grain yield and straw dry mass, and the number of larvae versus the straw dry mass were produced. Results indicated that the average grain yield reduction for both crops due to pest infestation was estimated at 36.1% for wheat and 50% for barley, but the individual reductions ranged 17.4-73.3%. The straw dry mass reduction was estimated at 29.9% for wheat and 16.5% for barley with individual reductions ranging between 8.4 and 44.8%. In addition, one positive correlation for the number of leafminer larvae versus the leaf area consumed was found. The estimated leaf area consumed per one larva was 0.30 cmβ and 0.38 cmβ for wheat and barley, respectively.