The alfalfa snout beetle or ASB was first detected on May 4, 1896. The ASB was introduced to the port of Oswego through shipping ballast from Europe.
In the 1920’s, alfalfa was introduced as new forage for the dairy industry. It wasn’t until 1933 that the ASB was discovered as a pest in multiple fields.
From 1939 to 1972 populations of the ASB were managed using poison baiting methods and heptachlor. In 1972 these methods were banned due to concern of environmental contamination.
From 1976 to 1986 ASB populations began to explode over a large area. It was not uncommon for 2 million beetles per acre to exist.
From 1988 to 1989 potential insecticides were evaluated as a stop-gap management option, but did not end up being an effective management tool.
From 1990 to 1995 potential biocontrol organisms were isolated from the soil. Those organisms are entomopathogenic nematodes. Laboratory, greenhouse, and field trials were conducted to demonstrate the effectiveness of the nematodes, which persist for at least five years. The nematodes reduced the ASB larvae by 90-94% and the stand loss was only 15%. Unfortunately root damage is severe and still occurs. Seventy seven varieties of alfalfa were planned and screened for ASB resistance. Multiple trials were conducted with no results showing resistance.
A replicated alfalfa trial was established in the field. Evaluation of the rooting type alfalfa trials indicated one variety retaining 78% of the original stand while all of the other varieties tested were severely impacted by alfalfa snout beetle larval feeding. By the end of the second year, even the alfalfa selection was virtually killed out by snout beetle larval feeding.
1996-1997 A breeding program was initiated to develop potential alfalfa varieties which were either more tolerant or resistant to alfalfa snout beetle feeding. This is not quick or easy research and will require 10-20 years of intensive research effort.
1995-2002 Biological control efforts with entomopathogenic nematodes (insect attacking) continued with field evaluations concerning persistence, application techniques using commercial sprayers, timing of application and dose rates. In 2002, a farm wide population crash was recorded for the first time. It became apparent that entomopathogenic nematodes had moved throughout the farm from test plots and were responsible for the snout beetle population crash.
2004-2012 Research focus changed to developing a “farmer friendly” nematode rearing and application technique. Extension efforts were refocused on working with farmers and agribusiness consultants, teaching them the new techniques and assisting them with nematode rearing and applications. Insect attacking nematodes have been inoculated into more than 150 snout beetle infested fields in 6 counties.
After screening more than 150,000 seedlings for snout beetle resistance with the backcrossing of survivors, the first field trial to evaluate resistant varieties was planted in 2008 with encouraging results. Subsequent trials have been planted annually on snout beetle infested land since 2008.
2012-2015 An additional 85,000 seedlings were screened for snout beetle larval resistance in the greenhouse, promising plants intercrossed and promising experimental lines tested in the field against snout beetle populations. As a result, Seedway 9558 SBR was first made available to producers in 2013.
Field trials planted using resistant varieties in Adams, NY and Lowville, NY was evaluated through the first two years of production. Alfalfa populations were selected for resistance to snout beetle for 7-9 cycles to determine differences in yield and root feeding damage.
NY-native persistent nematodes were made available for application on grower fields to reduce ASB populations by Cornell (Shields Lab). They require 2-4 years for full effectiveness determined by the application method. Producers are now able to purchase ready to apply nematodes to their own fields. Producers also have the option to purchase starter cups and rear their own nematodes which they then apply to their own fields.
During 2015 a cost-sharing program for NNY farms to promote farmer adoption was funded by NNY Agricultural Development Program Small Grants Program. This program was open to new and current participating producers, with preference given to those producers with no previous nematode treated fields. The program allowed interested new farms the opportunity to purchase bio-control nematodes at a 50% discount while returning farms received a 25% discount. The program also encouraged commercial applicators the opportunity to participate by applying biocontrol nematodes as a possible addition to their business structure.
To date, 77 farms have applied biological control nematodes on more than 250 fields covering 12,000-14,000 acres in six NNY counties.
2016 The Shields Lab will continue to offer farms interested in applying bio-control nematodes the option to purchase bio-control nematodes or assist farmers interested in rearing their own nematodes on their own farm with their own labor.
Plant breeders will continue their efforts to increase the resistance levels to snout beetle larval root feeding so alfalfa stands have a measure of durability against significant beetle populations.