The knowledge of the arrangements of dispersion of insect pests in soybean cultivars is needed to improve the monitoring and control. The objective of this study was to evaluate the spatial distribution of adults and nymphs of Euschistus heros in Bt and non-Bt soybean into two regions, under field conditions. The experimental area located in Dourados and Douradina, Mato Grosso do Sul. For the evaluations we used the method of cloth-to-beat, where we collected one sample per plot randomly from each experimental area. Evaluations were performed at 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98 days after emergence (DAE). For data analysis, the rates of dispersion (variance/average Morisita index and exponent k  Negative Binomial Distribution) and theoretical frequency distributions (Poisson, Binomial and Negative Binomial Positive) were estimated at 1-5 % probability. Adults of E. heros are arranged differently for Bt and non-Bt soybean and between regions, since in both cultivars and locations, individuals of the populations evaluated in probabilistic set arrangements negative binomial distribution (aggregate), Poisson (random) and positive binomial distribution (uniform), as the days after soybean emergence. The nymphs of E. heros showed aggregated spatial arrangement, being distributed similarly for Bt and non-Bt soybean and regions, setting a negative binomial distribution model.

Phytophagous stink bugs are major soybean pests, and knowledge of spatial distribution models of the pest in the crop is fundamental to establishing an appropriate sequential sampling plan, and thus, allowing the correct utilization of control strategies. This work aimed to study the spatial distribution of phytophagous stink bugs in soybean grown in different cropping systems and determine a sequential sampling plan. The experiment was conducted in Maracaju, MS, Brazil, during the agricultural year of 2012/2013. Soybean cultivars BRS 284 and SYN 1163 RR were placed in an experimental area comprising six fields (two soybean cultivars × three cropping systems). Sampling was performed weekly, using a beat cloth per plot and counting the number of stink bugs found, virtually throughout the soybean reproductive period. Concerning the statistical analyses, we used the dispersion indexes (variance‐to‐mean ratio, Morisita's index, exponent k of the negative binomial and Green's coefficient) and probabilistic methods of frequency adjustment (negative binomial and Poisson). Adult and nymph phytophagous stink bugs showed aggregate disposition in the field regardless of the cropping system, and their numbers were adjusted to the negative binomial probability distribution. There was no difference in the behaviour of adult and nymphs considering the tested cultivars. We elaborated a practical sequential sampling plan for phytophagous stink bug complexes, considering crops intended for the production of grains and seeds.

The objective of this study was to evaluate the levels of chlorophyll and agronomic performance of Bt and non-Bt soybeans. For the evaluation we used the chlorophyll meter (SPAD-502), which was collected randomly in the upper third (TS), middle third (TM) and lower thirds (TI). Evaluations were performed at 7, 14, 21, 28, 35, 42, 49, 56, 63, and 70 days after emergence (DAE). Used the randomized experimental design in a split plot design (2 x 3 x 10) with four replicates for analysis of chlorophyll content and factorial 2 x 2 (two cultivars and two regions) with four replications for the factors of production. For the region of Dourados, the highest chlorophyll levels were presented to 42 DAE for soybeans Bt and non-Bt, the TS and TI, for TM at 42 DAE for soybeans Bt and non-Bt to 35 DAE. In Douradina the highest levels of chlorophyll were for soybean at 28 DAE Bt and non Bt at 49 DAE in the lower third. For TM and TS cultivars Bt and non-Bt had higher chlorophyll content at 35 DAE. From the results obtained, it can be concluded that the Bt technology did not influence the chlorophyll content of soybean, the two cultivars showed similar levels, with higher concentrations in the middle third of the plants in the two regions studied. For agronomic attributes, plant height, first pod height, number of pods per plant and yield, Bt soybeans had higher values compared to non-Bt soybeans in two environmental studies.

To deploy the appropriate management of adults and nymphs of Euschistus heros (Fabricius, 1794) in soybean, we need to construct a sampling plan that allows estimate population density quickly and accurately. This research aimed to perform sequential sampling of adults and nymphs of E. heros in Bt and non-Bt soybeans. For the evaluations we used the method of cloth-to-hit, two regions in which the sample areas where we collected a sample randomly per plot of each trial were installed. Evaluations were performed at 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98 days after emergence (DAE). We adopted the model of contagious distribution, it was constructed a sequential sampling plan in accordance with the Sequential Probability Ratio Test (TSRP). The adopted control level two bugs (adults and nymphs) per cloth beat. The analysis showed two lines of decision: the upper, which is the condition that the adoption of a method of control is recommended, defined by S1 = 6.2449 +0.14244 n; and below, representing that the adoption of some method of control is not recommended, defined by S0 = -6.2449 +0.14244 n. The sampling showed a maximum expected number eight samples to determine the need or otherwise of control. For management based on economic injury level, the expected number of sample units is 17, indicated by the Sequential Probability Ratio Test Wald curve.

Knowledge of the dispersion of adults and nymphs of Edessa meditabunda in soybean model is needed to determine the control actions and thus enable proper use of strategies to avoid losses in production. This research aimed to conduct probabilistic analysis of the spatial distribution patterns of adults and nymphs of E. meditabunda in two regions in soybean Bt and non-Bt. For the evaluations, the method of cloth-to-beat was used, where one sample per plot was collected randomly from each experimental area. Evaluations were performed at 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91 and 98 days after emergence. For data analysis, the rates of dispersion (variance/average Morisita index and exponent k Negative Binomial Distribution) and theoretical frequency distributions (Poisson, Binomial and Negative Binomial Positive) at 5% probability were calculated. The peak population of adults and nymphs of E. meditabunda was observed in the reproductive stage of soybean Bt and non-Bt in Dourados and Douradina. From the results obtained, it can be concluded that the Bt technology had the spatial arrangement of adults and nymphs of E. meditabunda, and is set in probabilistic arrangements with negative binomial distribution (aggregate) in the two regions surveyed. In non-Bt soybeans for adults and nymphs of E. meditabunda, spatial arrangements had set in probabilistic arrangements of positive and negative binomial distribution (uniform), as the days after emergence, for the region of Dourados and Douradina.