عنوان مقاله [English]
Introduction: European red mite (Panonychus ulmi (Koch)) and two-spotted spider mite (Tetranychus urticae Koch) are the two major pests of deciduous trees and most of the acaricides used in the control of them in apple orchards of Iran. The early of these two mite damages on leaf chlorophyll contents caused plant retardation, reduce fruit size and quality in apple production. Extensive mite pest damages during the middle of spring and summer months not only caused complete leaves shedding but side effects of this unusual condition imposed shortages of nutritional on vigorously of infested apple trees in next year on apple production also. Most of the new acaricides introduced and registered here in the last two decades demanded and evaluated against apple mite pests. Reduce the hazardous risk of synthetic acaricides application, so many efforts since 1995 undertaken since 1995 for sustainable mite pest’s management and keeping environmental and natural enemies safer in apple orchards. Evaluation of organic pesticides in developed countries in control of apple pests received more attention mostly to overcome spider mite pest damages in the world. In Iran, the only sulfur powder was tested in 1954 against citrus russet mite and no other mineral as an acaricide tested on apple mite pests in Iran. In this study, for the first time, the effect of Kaolin doses investigated on active stages of European red mite in four major apple growing orchards of Iran. Concerned literature survey indicated that this the first in depended kaolin effects report from Iran.
Material and Methods: Different kaolin doses (3, 4 and 5%) against Panonychus ulmi infested apple orchards during investigated 2014. Effect of this pesticide was compared with registered acaricides such as Envidor (spirodiclofen 240 SC), floramite (bifenazate 24% SC), Danitol (fenpropathrin 10% EC), Ortus (fenpyroximate 5% SC), 1.5% detergent dishwashing along with water sprayed on apple trees as in uncontrolled treatment. Experiments conducted in different provinces of Iran (West Azerbaijan, Esfahan, Ardebil and Khorasan Razavi provinces during 2014). Treatment effectiveness was determined by random 40 apple leaves collected at the interval of one day before and 3, 7, 14 and 21 days after treatments. Active mite stages on the upper side of the apple leaf counted with the help of a stereomicroscope. Collected alive mite raw data from each treatment at different interval times, converted into morality% by Henderson-Tilton formula. Mean mortality% analysis variance done with SAS software. Grouping and ranking effects of each treatment carried out by DUNCAN methods.
Results and Discussion: Mite mean density before treatments on apple leaves among treatments found varied during 2014 in different provinces. The highest mean of mite out of 40 leaves before treatments in West Azerbaijan, Esfahan, Ardebil and Khorasan Razavi provinces recorded 11.60±0.28, 13.52±1.29, 11.85±0.32 and 4.75±0.15 respectively with total apple leaves infestation of 65 to 80% in all provinces. Lower doses (3 and 4%) of kaolin pesticides in the control of mite pests in all experimental stations except in Ardebil observed very weakly and less than 50% up to 14 days after. The highest mite mortality% time up to 7 days after treatments for 5% kaolin dose recorded 75.97% and 78.70 up to 7 days in Oromia and Ardebil and up to 14 days after observed 66.68%, 75.23% in Esfahan and Khorasan Razavi provinces respectively. A sharp reduction in apple mite pest control recorded at 21 days sampling interval for kaolin 5%. All kaolin doses sprayed on apple trees found without phytotoxicity during the hot and dried period of sampling time in all places. Expected control with 5% kaolin application at the early stages of P. ulmi activity for a once during the growing season is possible.
Conclusion: Application 5% kaolin at the lower incidence of Panonychus ulmi for once during the growing season in apple orchards recommended.