Resistance of different pinto bean lines/varieties to two-spotted spider mite, Tetranychus urticae Koch under laboratory and field conditions
Paper ID : 1070-IPCA4
zarir saeidi1, arsalan Khalili-Moghadam *2
1Agricultural and Natural Reaserch Center, Chaharmahal and Bakhtiari, Shahrekord, Iran
2Department of Plant Protection, Faculty of Agriculture, Shahrekord University,  Iran.
Two-spotted spider mite (TSSM) (Tetranychus urticae Koch) is considered as the most important pest of bean in different parts of the world. In this study, 35 lines/varieties of pinto bean were evaluated for resistance to the mite in two stages. In the first stage, they were studied using leaf disk bioassay under laboratory conditions (25 ± 2 oC, RH 50 ± 10% and photoperiod 14 L: 10 D). Based on the results, line ‘D521’ (7.52 ± 1.23 eggs/female/day) supported the highest, whereas, lines ‘L1’ (1.46 ± 0.23), ‘J29’ (1.60 ± 0.26) and ‘L19’ (1.69 ± 0.59 eggs/female/day) supported the lowest level of oviposition. The highest and lowest level of damage were observed on leaf disk of ‘D521’ (5.5±0.40) and ‘L19’ (1.8 ±0.37), respectively. The studied lines were classified into five groups, based on the mite response to the host (oviposition and mortality) and host response to the mite (damage score). In the second stage, population density and damage caused by TSSM on eight selected lines were studied under field conditions during two successive years (2009-2010). The experiment was arranged in completely randomized block design with four replications in Lordegan fields, Chaharmahal va Bakhtiari province, Iran. Population density of TSSM was recorded at weekly intervals, beginning from the seedling stage and continued to harvesting time. Moreover, at the harvesting time the yield and yield components including; the number of pods/plant, number of seeds/pod and weight of 100 seeds were compared among the treatments. The highest number of mite was recorded on line ‘L29’ (120.20 ± 18.79 mites/ 2 cm2 of the abaxial leaf surface in 2009) and line ‘D3’ (55.53 ± 5.68 in 2010) whereas, the lowest on line ‘L1’ (22.51 ± 4.96 and 9.33 ± 0. in 2009 and 2010, respectively). The highest yield/plant was recorded in line ‘J29’ (16.2 ± 3.1 and 15.94 ± 3.4 g/plant) followed by line ‘D3’ and line ‘L19’, whereas, the lowest in lines ‘L1’ (0.63 ± 0.08 and 0.19 ± 0.07 gr/plant in 2009 and 2010, respectively). Resistant lines /varieties could minimize TSSM damage, reduce pesticides application, protect environment and guarantee stability of production.
Bean, Susceptibility, Two -spotted spider mite, Population density, Infestation
Status : Abstract Accepted (Poster Presentation)