Breeding Alfalfa Varieties with Resistance to Alfalfa Snout BeetleJamie Crawford, Julie Hansen, and Don Viands, Department of Plant Breeding and Genetics; Elson Shields and Antonio Testa, Department of

Entomology; Doug Shelmidine, Sheland Farms Adams NY.

Alfalfa snout beetle infestation in New York

Alfalfa snout beetle (ASB), is the most destructive insect pest of alfalfa in Northern New York (NNY), and is continuing to spread. This pest causes severe yield and stand losses on alfalfa by larval feeding on alfalfa roots. New infestations are often mistaken for winter injury since the majority of plants die after the last harvest and before spring growth.

Left: Undamaged alfalfa root

Right: Alfalfa roots showing ASB damage

A Field Trial for Evaluating Breeding Progress for Alfalfa Resistant to Alfalfa Snout Beetle -

Resistance is indicated by lower root feeding damage rating (1= no damage to 5=severe damage)

2.40

2.50

2.60

2.70

2.80

2.90

3.00

ASB Cycle 0 ASB Cycle 5 Seedway 9558Cycle 0

Seedway 9558Cycle 4

Populations

Ro

ot F

eed

ing

Dam

age

Rat

ing

A breeding program to develop ASB resistant alfalfa was initiated by Cornell University Forage Breeders. Since field screenings were not reliable, a greenhouse screening method was developed by Cornell Entomologists, E. J. Shields and A. Testa. To date, breeders have completed six to seven cycles of selection, screening more than 150,000 seedlings over seven years.

9% Gain in Resistance

Two of the three populations evaluated showed improvements in root ratings. Cycle 4 or 5 had 0.25 or 9% less root damage than Cycle 0.Insect Fact: Did you know that alfalfa snout beetle larvae live underground for two years before emergingas adults!

A field trial to test the breeding progress was seeded on April 21, 2008 at Sheland Farms in Adams NY (Jefferson County).