BIOLOGICAL ASPECTS AND THERMAL REQUIREMENTS OF THE BIRD CHERRY-OAT APHID, Rhopalosiphum padi (LINNAEUS), REARED ON WHEAT SEEDLINGS

Abstract

The bird cherry-oat aphid, Rhopalosiphum padi (Linnaeus) was studied at 15, 20 and 25 o C constant temperatures. Wheat seedlings were offered for feeding and maintaining the aphid, R. padi using the Punctured Ependorf Tube Technique. R. padi showed the longest life cycle duration at 15 o C as 12.77±1.71days. This duration decreased to 8.36±0.79 and 6.74±0.56 at 20 and 25 o C, respectively. The fecundity rate was the lowest (35.41 progenies/female) at 25 o C. It was higher at both 15 and 20 o C as 50.2 and 53.429 progenies/female, respectively. The longest life span was recorded at 15 o C as 49.47±16.43days. This duration decreased to 34.05±6.22 and 19.47±4.16 days at 20 o C and 25 o C, respectively. The lower developmental threshold (t0) for the R. padi nymphal instars; first, second, third and fourth were 2.216, 6.958, 3.432 and 0.164 o C, respectively. The estimated t0 values for the life-cycle and generation time were 3.537 and 3.976 o C, respectively. The thermal requirements (K) for each nymphal instar; first, second, third and fourth were, life-cycle and generation time were 45.

The Effect of Wheat Varieties on the Biological Attributes of Corn Leaf Aphid, Rhopalosiphum maidis (Fitch) (Hemiptera: Aphididae) under Laboratory Conditions

“…On the other hand, the lowest developmental time was recorded when aphid reared on Misr-2 variety (4.75 days) followed insignificantly by Suhag-5 variety. Similar trend was recorded for total developmental time of nymphal stage (6.74±0.56 days) of R. padi which was reared on wheat at 25 C° by El-Fatih et al (2015). On the other hand, Taheri et al (2010) investigated the nymphal stages durations of R. padi on six wheat varieties they indicated that the six examined wheat varieties differed significantly.…”