the toxicity of imidacloprid and pirimicarb for all stages of the melon aphid, aphis gossypii glover, were investigated under laboratory conditions (25 ± 1 oc, 65 ± 5% r.h. and a photoperiod of 16:8 (l: d) h.) using a leaf dipping method. these pesticides were very toxic for first instar nymphs of a. gossypii with lc50 values of 17 and 220.2 ppm for imidacloprid and pirimicarb, respectively. fo...

Soybean, Glycine max L., and elodea, Elodea canadensis Michx, leaves were exposed to sublethal and lethal temperatures and examined by light microscopy. Loss of chlorophyll and swollen chloroplasts were observed in cells of elodea leaves exposed to sublethal temperatures. At the thermal death point of leaf cells of elodea and soybean, there was a disorganization of the tonoplast membrane, plasm...

Enhancement of salt (NaCl) tolerance by pretreatment with sublethal dose (50 mM) of NaCl was investigated in V. radiata seedlings. NaCl stress caused drastic effects on roots compared to shoots. Accompanying reductions in length, number of root hairs and branches, roots became stout, brittle and brown in color. Salt stress caused gradual reduction in chlorophyll, carotenoid pigment contents and...

The aim of this study was to determine the toxicity of the aqueous extract of neem leaves, a product extensively used in fish-farms as alternative for the control of fish parasites and fish fry predators, for the neotropical fish Prochilodus lineatus. The 24 h LC(50) of neem leaf extract for juveniles P. lineatus was estimated as 4.8 g L(-1); the fish were then exposed for 24 h to 2.5, 5.0 and ...

Neonicotinoids are subjected to vigilance because of environmental contaminations and deleterious effects on bees. Imidacloprid (IMI) is one of the most representative insecticides of this family. At chronic exposure, concentration-effect relationships are non linear. An insect model should allow a better description of this toxicity. We compared the lethal concentration 50% (LC50) of IMI for a...

The widespread usage of neonicotinoid insecticides has sparked concern over their effects on non-target organisms. While research has largely focused on terrestrial systems, the low soil binding and high water solubility of neonicotinoids, paired with their extensive use on the landscape, puts aquatic environments at high risk for contamination via runoff events. We assessed the potential threa...

Huanglongbing (HLB) is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasi...