COMPARATIVE PREFERENCE AND POPULATION GROWTH OF THE PEA APHID (ACYRTHOSIPHON PISUM) IN FIVE PEA (PISUM SATIVUM L.) GENOTYPES

Abstract

Plant genotypic resistance to herbivores aid pest management strategies through less insect choice to establish in the plant and/or reduced insect population growth. The pea aphid (Acyrthosiphon pisum) is a major pest in cultivated peas for the agrifood industry, but it is unknown whether commercial pea cultivars used in Chile express resistance mechanisms to this insect. In greenhouse experiments, the preference and population growth of the pea aphid in 5 commercial genotypes of pea: Ashton, Talbot, Sonata, Bolero and Perfect Freezer were determined for both alate and apterous individuals. When aphids were given the option to choose among the five genotypes, the proportion of alate individuals that established was as follows, 15 ± 4% in Talbot, 13 ± 4% in Ashton, 9 ± 3% in Bolero, 5 ± 2% in Perfect Freezer, and 3 ± 2% in Sonata (P = 0.048). On the other hand, 20% of apterous individuals choose to settle on cultivar Ashton over the other varieties (P <0.001). The reproductive capacity of aphids also differed among pea genotypes. Starting with one first instar nymph in each of the 8 replications, the average population of aphids per plant after 42 days was 289 ± 45 in Sonata, 165 ± 38 in Ashton, 159 ± 34 in Bolero, 105 ± 30 in Perfect Freezer and 39 ± 21 in Talbot (P <0.001). In conclusion, slight differences in terms of the preference of aphids were found, and marked differences in population growth potential in pea genotypes. Yield in grams per plant of genotypes was as follows: Sonata 9.56 ± 2.26, Talbot 12.53 ± 1.95, Ashton 17.45 ± 0.56, Bolero 17.49 ± 2.38 and Perfect Freezer 18.01 ± 1.37; showing that without insecticide treatment, pea yield in Sonata was the lowest.

Keywords: pea, host-resistance, aphid

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