CEPAVE   05420
CENTRO DE ESTUDIOS PARASITOLOGICOS Y DE VECTORES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SURVIVAL FOLLOWING POST-LEPIDOPTERAN INSECTICIDE APPLICATIONS IN SOYBEANS
Autor/es:
SOSA, M.A; ALMADA, M. S.; VITTI, D. E.; ZUIL, S.G.; LÓPEZ, R.
Lugar:
Durban
Reunión:
Congreso; WORLD SOYBEAN RESEARCH CONFERENCE IX; 2013
Institución organizadora:
World Soybean Research
Resumen:
The purpose of the refuge in a resistance management programme is to allow survival of susceptible individuals to delay the development of resistant insects. The objective of this study was to quantify the levels of survival at different levels of damage and insecticide application. The experiment was carried out at INTA EEA Reconquista, Santa Fe (Argentina), in a soybean crop (Munasqa, GM VIII) under no tillage with a 52cm row spacing. Treatments were arranged in a randomized complete block design in plots of 41.6m2, with three replications. The crop was exposed to natural attack by Lepidopteran pests. Treatments were: i) 1-5 no residual insecticide (100 cc/ha cypermethrin 25%), ii) 6-10 residual insecticide (120 c/ha methoxyfenozide 24% (IGR), applied when defoliation levels 5, 10, 15, 20 and 30% were reached, regardless of the phenological state, and iii) 11 control treatment. Analyzing the evolution of the percentage of leaf area damaged, treatments clearly differed and generated two groups with different percentages of damage. The group less damaged, (treatments 1, 2, 6 and 7) was maintained throughout the growing season below 10% defoliation, whereas the group with the most damage (treatments 3, 5, 10, 9, 8 and 4) reached 35% defoliation at R1 and remained in a range of 25- 35% at R2, which started to decline in R4-R5 to reach percentages of damage similar to the less damaged group. The control treatment (11) accompanied the evolution of this group, but extended its period of maximum defoliation to R3. The first group differed significantly from other treatments and showed the lowest values (<10%) of average leaf area damaged throughout the crop cycle. When comparing the number of larvae in the treatment maintaining the percentage of leaf area damage of <10% (co-incident with the threshold set by INTA of 8-10% leaf area damage at R3-R6) with the control treatment, this group can be proposed as refuge management according to this threshold. This would generate 50% of susceptible individuals in comparison to an untreated refuge without yield decreases. Treatments 1, 2, 6 and 7 produced the highest yield (3.662kg/ha average) and were statistically different from other treatments using insecticide (2.637kg/ha average) and with the control (1.607 kg / ha). In conclusion, the management of the refuge strip must be in accordance with thresholds using INTA and IGR insecticides, so that the refuge produces the maximum number of susceptible individuals without affecting grain production.2, with three replications. The crop was exposed to natural attack by Lepidopteran pests. Treatments were: i) 1-5 no residual insecticide (100 cc/ha cypermethrin 25%), ii) 6-10 residual insecticide (120 c/ha methoxyfenozide 24% (IGR), applied when defoliation levels 5, 10, 15, 20 and 30% were reached, regardless of the phenological state, and iii) 11 control treatment. Analyzing the evolution of the percentage of leaf area damaged, treatments clearly differed and generated two groups with different percentages of damage. The group less damaged, (treatments 1, 2, 6 and 7) was maintained throughout the growing season below 10% defoliation, whereas the group with the most damage (treatments 3, 5, 10, 9, 8 and 4) reached 35% defoliation at R1 and remained in a range of 25- 35% at R2, which started to decline in R4-R5 to reach percentages of damage similar to the less damaged group. The control treatment (11) accompanied the evolution of this group, but extended its period of maximum defoliation to R3. The first group differed significantly from other treatments and showed the lowest values (<10%) of average leaf area damaged throughout the crop cycle. When comparing the number of larvae in the treatment maintaining the percentage of leaf area damage of <10% (co-incident with the threshold set by INTA of 8-10% leaf area damage at R3-R6) with the control treatment, this group can be proposed as refuge management according to this threshold. This would generate 50% of susceptible individuals in comparison to an untreated refuge without yield decreases. Treatments 1, 2, 6 and 7 produced the highest yield (3.662kg/ha average) and were statistically different from other treatments using insecticide (2.637kg/ha average) and with the control (1.607 kg / ha). In conclusion, the management of the refuge strip must be in accordance with thresholds using INTA and IGR insecticides, so that the refuge produces the maximum number of susceptible individuals without affecting grain production.