WEED AND INSECT CONTROL IN CRANBERRY BEDS
Horticultural Crops Research
2013 Annual Report
1a.Objectives (from AD-416):
1. Develop and assess new controls for perennial weeds in cranberry beds.
2. Develop and assess controls for blackvine weevil in cranberry beds.
3. Assess organophosphate alternatives for insecticide management on cranberry beds.
1b.Approach (from AD-416):
Field trials will be implemented across numerous growers’ cranberry beds infested with yellow loosestrife (Lysimachia terrestris). Trials will consist of mesotrione, rimsulfuron and quinclorac applied alone and in all herbicide combinations. Research will be conducted to assess adulticides and larvicides for the control of blackvine weevil. Adulticides - each treatment will be applied at the first sign of adult emergence. Larvicides - treatments will be applied to weevil-infested cranberry beds at the end of egg laying in August. Research will be conducted to assess if any of the new alternative insecticide chemistries are as effective for fireworm control as organophosphates when applications are made via chemigation. Documents Grant with Washington State University. Formerly 5358-22000-032-15G (12/10). Formerly 5358-22000-036-04G (8/2011).
This research was conducted in support of NP 304 objective 3B of the parent project. Results on herbicide screening trials in 2012 and 2013 indicate that the herbicide indaziflam provided excellent long-term pre-emergent control of several important weeds in cranberries with no crop phytotoxicity. This chemistry, because of its efficacy, crop safety, and registrant support, has excellent registration potential for cranberries. The herbicides chlorimuron and quinclorac provided year-after treatment control of Lysimachia terrestris, the main cranberry weed pest in PNW cranberries. A full registration was obtained for quinclorac and for chlorimuron. Both herbicides received rapid widespread adoption by the industry in Oregon and Washington.
Trials were conducted to assess efficacy of blackvine weevil larvicides and adulticides. Spring-applied Metarhizium anisopliae strain F52 was efficacious as a larvicide. Numerous other chemistries were assessed for adulticidal activity following foliar feeding; none were overly effective. Fenpropathrin, however, had good adult knockdown activity.
Multiple whole-farm trials for chemigation treatment of blackheaded fireworm (BHFW) using rynaxypyr, methoxyfenozide and spinetoram, were conducted. All chemistries had excellent efficacy as larvicides. These trials were conducted as paired studies comparing conventional OP insecticides. Efficacy was comparable, but the reduced-risk farms had greater populations of beneficial insects. In small trial studies, rynaxypyr had up to 21 days of field activity; methoxyfenozide had 14 days. Both chemistries had activity on neonatal larva when applied prior to egg hatch.