No abstract

No abstract

The objective of this work was to evaluate the glyphosate herbicide effect on Hymenaea stigonocarpa Mart. ex Hayne seedlings. A randomized block design with 5 replicates was used with an experimental unit composed of one H. stigonocarpa plant in 5L pots. The treatments were: 0 (control); 9.6; 240; 480; 960 g a. ha− 1 of glyphosate. Evaluations were performed 24 hours and 60 days after application. Gas exchange, respiration, photosynthesis, visual, anatomical and histochemical evaluations were carried out with leaves from the middle third being collected, and the growth in relation to the two dates was measured and recorded. The growth analysis showed that the seedlings showed an increase in stem diameter, a decrease in leaf number and an increase in height. There were increases in photosynthetic, electron transport and transpiratory rates, and in the effective yield of photosystem II one day after the glyphosate application. The plants then showed a reduction in transpiratory rate and a reduction in Fv/Fm at 60 days after application. With these studies we can conclude that the Hymenaea stigonocarpa species is able to survive after contact with the glyphosate herbicide, with no visual and/or anatomical damage, along with positive increases in growth and physiological characteristics.

The soybean looper, Chrysodeixis includens, is a primary soybean pest that reduces crop productivity. This work examined control of C. includens populations with methanolic extract of Serjania erecta, a native Cerrado plant, while minimizing risks to pollinators, natural enemies and the environment. Serjania erecta specimens were collected, identified, and subjected to methanol extraction. Bioassays were performed using newly hatched and second-instar caterpillars and different extract concentrations on the diet surface to obtain IC50 values. Two replicates, containing 10 caterpillars, were established in triplicate. The IC50 values were 4.15 and 6.24 mg of extract mL−1 for first-instar and second-instar caterpillars, respectively. These growth inhibition results informed the extract concentrations assessed in subsequent development inhibition assays, in which the pupal weight was higher under the control than under the treatments. Extract treatments increased the duration of the larval, pupal and total development. The potential of different concentrations of S. erecta extract to inhibit the enzymes carboxylesterases was also evaluated. Carboxylesterases activity decreased by 41.96 and 43.43% at 7.8 and 15.6 μg mL−1 extract, respectively. At 31.3 μg mL−1 extract, enzymatic activity was not detected. Overall, S. erecta leaf methanolic extract showed inhibitory potential against carboxylesterases.