Effect of geographical directions, height and the color of yellow traps in capture of Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824) in citrus orchards

Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824) (Dip.: Tephritidae) is one of the most destructive agricultural pests in the world. To replace chemical control methods, as well as the timing of the peak population of Mediterranean fruit fly, the yellow sticky vertical traps were used in this study. The research was carried out in some citrus orchards of various cities of Mazandaran province of Iran, during the four months from August to November 2016. To determine the best type of yellow color to trap this fly, four types of yellow colors with measured wavelength of reflection, including the fluorescent yellow (538 nm), lemon yellow (574 nm), yellow (602 nm) and amber yellow (641 nm), were used. Also, to determine the best geographical direction and appropriate height for installation of yellow cards, four cardinal directions and five different heights of 1, 1.5, 2, 2.5 and 3 m above ground level were determined and the cards were installed. The results of mean comparison of captured flies in different treatments showed that there are significant differences between all of them. The results indicated that the fluorescent yellow, heights of 1.5 and 2 m, the south direction, and month October had the highest number of capture in yellow cards.</p

Toxicity of selected biorational insecticides to Pulvinaria aurantii Cockerell and its predator, Cryptolaemus montrouzieri Mulsant in citrus field

The citrus cottony scale, Pulvinaria aurantii Cockerell, is the most important pest of citrus orchards in northern Iran in recent years. Owing to the harmful impacts of chemical insecticides, the use of biorational pesticides seems a safe and convenient way to control this pest. The present investigation was set up to study contact toxicity of various biorational and chemical compounds on the first, second instar nymph and overwintering adult of the citrus cottony scale, P. aurantii, and its predator, Cryptolaemus montrouzieri Mulsant under field conditions. The results indicated that the highest percentage of mortality of first instar nymph of the citrus cottony scale was observed in the Dayabon treatment of 9 and 10 ml/L, 100.0% ± 0.0% and the lowest percentage was observed in Palizin treatment of 1.5 ml/L, 34.7% ± 2.9%. In the second instar nymph, the highest mortality was seen in the Dursban treatment of 2 ml/L, 94.7% ± 2.4% and the lowest mortality in the Palizin treatment of 1.5 ml/L, 30.0% ± 2.3%. Also, for overwintering adults Dayabon 10 ml/L caused the highest mortality, 96.0% ± 4.0% during 24 h. In the case of ladybird insects, the highest and lowest percentage of mortality was observed in the Dursban treatment of 2 ml/L, 76.7% ± 8.8%, Dayabon 5 ml/L, and Palizin 2 ml/L, 3.3% ± 3.3%, respectively. The highest and lowest mortality rate of larvae of ladybird was estimated in the Dursban treatment of 2 ml/L, 83.3% ± 3.3% and Dayabon 5 ml/L, 3.3% ± 3.3%, respectively. Also, for overwintering predator adults Palizin 1.5 ml/L had the lowest mortality, 3.3% ± 3.3% during 24 h and this rate remain unchanged after 96 h after treatment. According to the results obtained, treatments with Dayabon 9 and 10 ml/L, can be a viable alternative to other high-risk chemical pesticides in addition to effectively controlling citrus cottony scale without having any adverse impacts on predator ladybird