Monitoring of Biocontrol of the Sugar Cane Stalk Borer Trevor Falloon Sugar Industry Research Institute Kendal Road, Mandeville
Sugar Cane Stalk Borer Diatraea saccharalis F (only species in Jamaica) Lepidoptera: Noctuidae Adult moth Native to Western Hemisphere Original Host corn, wild grasses Switched to cane after import in 1493
Damage Tunnels into stalk Allows entry of red rot fungus Little measurable loss in tonnage Sucrose loss estimated at 0.02 to >1.6%
Impact Traditionally 2 nd most important insect pest Canefly No. 1 pest With canefly receding in importance, now the borer is No. 1 Damages approximately 7% internodes islandwide Irrigated areas > 10%, Rain-fed <5%
Control Chemical control of borer not recommended in Jamaica Long history of Biological Control Began with egg parasites Trichogramma spp Later focus on importing larval parasites: Metagonistylum minense (Amazon Fly) Paratheresia claripalpis Allorhogas pyralophagus Cotesia (Apanteles) flavipes
Control Cont d Pupal parasite briefly attempted: Pediobius furvus - failed Only successful establishment Cotesia flavipes Native larval parasites: Lixophaga diatraeae (Cuban Fly) and Agathis stigmaterus (a wasp) Predators: Euborellia spp
Purpose Study monitors the success of C. flavipes in parasitising the borer and in reducing stalk damage
Monitoring Parasitism of the Borer Cotesia imported from Pakistan via CIBC, Trinidad Mass reared in Mandeville Released in fields, primarily in heavily infested southern irrigated zone Borers collected from the field Reared under observation in laboratory Record kept of parasite emergence
Field Collection
Monitoring Borer Damage Levels Periodic stalk damage surveys Random selection of stalks from fields Splitting, examination of internal stalk damage Conducted primarily on irrigated estates To determine % internodes bored 5% considered economic threshold
Results Borer Parasitism 1983 First field recovery of Cotesia Site Rowington, New Yarmouth 1987 establishment declared permanent Rearing release phased out Pre Cotesia total parasitism 22% Post Cotesia total parasitism 37% (in 1987)
Results Borer Parasitism 1999 Very low levels of Cotesia detected at New Yarmouth 2000 Cotesia imported from Barbados Rearing release resumed In 2003-04 New Yarmouth imported batches of Cotesia from Guatemala for lab rearing and field release (project discontinued after hurricane Ivan)
Seasonality of Parasitism Early growing season Cuban Fly dominant Later Cotesia catches up and surpasses Cuban Fly At New Yarmouth, Farm 1 Mar-Nov 2007: No Cotesia recovered, Cuban Fly 7-23% Feb-Apr 2008: (in same zone) 8 26% Cotesia parasitism, Cuban Fly: 0-9%
Antagonism Antagonism between Cotesia and Cuban Fly (Early sign, 1983, Cotesia 18%, Cuban Fly 5%) Consequence, except shortly after establishment No cumulative increase in total parasitism Cotesia tends to displace Cuban Fly Cuban Fly bigger, stronger flyer early coloniser, but single parasite per host Cotesia greater fecundity - 20-80 parasites/host, able to overwhelm other parasites on same host - but tiny, probably less wind resistant
Results Borer Parasitism 2003 - Milk Spring, Monymusk 13% parsitised by Cotesia New Yarmouth - 8% by Cotesia Resurgence of Cuban Fly (high of 32% in a New Yarmouth field)
Fig. 1: % Internodes Bored, New Yarmouth* 20 18 16 14 12 10 8 6 4 2 0 % Damage % Bored 1984 1987 1990 1993 1996 1999 2002 2005
Results - Stalk Damage Failure to reduce stalk damage Levels now no better than before start of the programme Brazil no measurable change in damage levels after 10 years of massive releases of Cotesia Venezuela found no higher total parasitism following combination of Cotesia with local Amazon Fly
Conclusion Monitoring: confirms field establishment of C. flavipes in the sugar industry Shows seasonality in parasite levels Suggests antagonism between local and imported parasites Shows no net increase in borer parasitism Shows no sustained decrease in stalk damage Questions efficacy of C. flavipes in Jamaica
Thank You!