• Korean journal of applied entomology
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• v.52 no.4
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• pp.415-425
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• 2013

The yellow tea thrips, Scirtothrips dorsalis (Thysanoptera: Thripidae), has been regarded as a minor pest on citrus on Jeju Island. However, the damage of yellow tea thrips has gradually increased since 2007. This study was conducted to develop a forecasting model for generation peak time of S. dorsalis by using degree-days. Simple linear regression analysis was applied to determine the relationship between the generation number (x, dependent variable) and degree-days (y, independent variable). As a result, two regression models were established: citrus-based model (y = 310.9x + 69.0, $r^2$=0.99) and green tea-based model (y = 285.7x + 84.1, $r^2$=0.99). The models was fitted by independent data sets obtained from 2013 and evaluated using the technique of RSS (residual sum of square) and ${\chi}^2$-test. The green tea based-model showed a good fitting ability. The discrepancy between model outputs and actual data, and the practical application of models were discussed.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.311-315
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• 2014

Lantern fly(Lycorma delicatula) is a major invasive pest that causes withering symptom of agricultural crops by sucking tree sap and sooty mold symptom by producing honeydew. This study was conducted to investigate the occurrence pattern of lantern fly in grape orchards in Gyeonggi area and the effect of winter temperature on L. delicatula egg survival during 2010 to 2013. In Gyeonggi areas, overwintered L. delicatula eggs began to hatch from early May and nymphs peaked in mid May. Adults emerged from late July and laid eggs until early November. The survival of L. delicatula eggs during overwintering was largely affected by winter temperatures. The relationship between the number of days below a threshold temperature (x) in January and the survival rate of overwintering L. delicatula eggs (y) was using linear regression model. The best model selected by the lowest RSS (residual sum of square) between predicted and actual survival was y = -1.0486 x + 94.496 ($R^2=0.7067$) with $-11^{\circ}C$ of threshold temperature. These results should be helpful to conduct L. delicatula management programs, since the results provided relivable prediction for the winter survival of L. delicatula eggs and the phenology of egg hatch in the spring.