Journal of Insect Science: Vol. 7 | Article 25

Table 1. Susceptibility of two wheat cultivars to clonal lines of the aphid, Schizaphis graminum, that differ in their ability to transmit Barley yellow dwarf virus–PAV or Cereal yellow dwarf virus–RPV.

Virus	Transmission Class ¹	Amigo Mean score ²	Largo Mean Score ²
BYDV-PAV	Efficient (>45%)	1.9 (0.2)	3.1 (0.2)
BYDV-PAV	Intermediate (7–45%)	2.7 (0.1)	2.8 (0.2)
BYDV-PAV	Inefficient (<7%)	2.3 (0.2)	2.9 (0.2)
		F_2,137=5.16, P=0.01	F_2,125=0.50, P=0.61
CYDV-RPV	Efficient (>61%)	2.1 (0.1)	3.2 (0.2)
CYDV-RPV	Intermediate (18–61%)	2.5 (0.2)	2.6 (0.2)
CYDV-RPV	Inefficient (<18%)	2.1 (0.3)	2.9 (0.3)
		F_2,115=2.12, P=0.13	F_2,112=2.23, P=0.12

¹Eighty F1 genotypes of S. granimum were divided into three categories, efficient, intermediate, and inefficient, based on their ability to transmit BYDV-PAV or CYDV-RPV. The percentages for each Transmission Class indicate the range of transmission efficiencies for all the aphids in that class.
²Susceptibility was scored as 1 to 4 based on when symptoms of feeding damage were visualized on leaf tissue: 1 = necrotic symptoms by 4 days, 2 = necrotic symptoms by 8 days, 3 = necrotic symptoms by 12 days, 4 = no visible necrotic symptoms. Experiments were repeated 2 to 4 times. Standard deviations are in parentheses.