Monitoring citrus thrips, Scirtothrips aurantii Faure (Thysanoptera, Thripidae), with yellow card traps and the effect of latitude on treatment thresholds
1990
Grout, T.G. (Citrus Exchange, Port Elizabeth (South Africa)) | Richards, G.I.
Comparisons between fluorescent 'Saturn Yellow' traps on the shady, southern side of the tree and non-fluorescent yellow card traps on the sunny, northern side of the tree were conducted on orange trees at different latitudes in South Africa. The smaller card traps caught significantly more (P below 0.01) citrus thrips than the Saturn Yellow traps at all latitudes south of 24 degrees S and this difference between trap types increased with latitude. Treatment thresholds for the card traps were estimated from regression equations relating the two different trap types by substitution previously established treatment thresholds for the Saturn Yellow traps. These card trap treatment threshold estimates were directly proportional to latitude (r(2) = 0.98). The threshold estimates for the southernmost latitude (33 degrees S) were verified at nine orchards using yellow polyvinyl chloride card traps
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