Transcript of "Crop protection integrated control of macadamia pests in south africa with specific emphasis on stink bugs - schalk schoeman"
Integrated control of macadamiapests in South Africa with specific emphasis on stink bugs Schalk Schoeman
Introduction• Understand the problem• Difficult to monitor for the stinkbugs (no pheromones!!)• Low tolerance for damage• Bugs migrate between various crops as well as wild hosts• Most chemicals really only work for a few days• Integrate/coordinate control between a number of crops.• Website regarding macadamia monitoring a beginning but more is needed
Materials and methods• Monitoring with branch shaking method since the spring of 2010• Nut dissection during the early part of the season• Pheromones for the tortricid complex• Quantification of eggs, larvae as well as damage up to physiological maturity• Two localities – unsprayed mixed cultivar orchards
Relative seasonal abundance - Nelspruit 40 35Total number of stinkbugs/10 trees 30 25 20 15 10 5 0 n d j j f mm a a mm j j j j a s s o o n n d d j j f f mm a a m 2010 2011 2012
Overwintering/diapause of the two spotted bug - Nelspruit2010
Overwintering/diapause of the two spotted bug - Friedenheim
Seasonal succession of indigenous stinkbugs at Nelspruit 120 100 80Percentage 60 40 20 0 n d j j f mm a a mm j j j j a s s o o n n d d j j f f mm a a mm j j j j 2010 Two spotted bug Other pentatomid bugs 2012
Seasonal succession of indigenous stinkbugs at Friedenheim 120 100 80Percentage 60 40 20 0 o o n n n n d d d j j j j f f f f f mmmm a a a mmmmm j j j j j j a Weeks 2011 Two spotted bug Other pentatomid bugs 2012
Relative seasonal abundance of the coconut bug2011 2012
80 Host switching behaviour 70Number of damaged fruit/5 trees 60 50 40 30 20 10 0 o o n n n n n d d d d j j j j j f f f f m m m m Litchis
80 Host switching behaviour 70Number of damaged fruit/5 trees 60 50 40 30 20 10 0 o o n n n n n d d d d j j j j j f f f f m m m m Macadamia Litchis
140 Host switching behaviour 120Number of damaged fruit/5 trees 100 80 60 40 20 0 o o n n n n n d d d d j j j j j f f f f m m m m Avocado Macadamia Litchis
Relative seasonal abundance of nut borer moths in relation to damage - Nelspruit
Relative seasonal abundance of nut borer moths in relation to damage - Friedenheim
Conclusions• Summer peak of two spotted bug ± 1220 degree days• Autumn peak of two spotted bug ± 2220 less well defined• Coconut bug is important !! – check for fallen nuts during December• Two spotted bug overwinter as adults and nymphs• Very low population levels during early summer – only adults• Other bugs migrate into macadamia orchards during winter but don’t breed.• Moths migrate into mac orchards ± 9 weeks after full bloom.• Mating and oviposition takes place soon afterwards• Best time for spraying a contact insecticide - ± 2 weeks after peak moth flights are recorded during Nov/Dec• Scouting for both complexes will be available on a website before the new season.• Website will be updated weekly• Initially Nelspruit area but Levubu and KZN will be added through the season
Acknowledgements• Subtrop• Members of the stink bug working group and particularly Gerhard Nortje• ARC-ITSC• Colleen Hepburn• Prof. Ben Botha
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