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Xenylla welchi was used to evaluate toxicity of two herbicide formulations, pretilachlor (50 EC) and pendimethalin (30 EC) under laboratory conditions. Twenty four hours LC₅₀ value of pretilachlor and pendimethalin formulations on Xenylla welchi were 72.7 and 190.0 g a.i/ha respectively which were less than their corresponding recommended agricultural doses. Again pretilachlor attained fastest LT₅₀ (110 min) followed by pendimethalin (140 min). Significant reductions in hatching success were noted with the application of both the herbicide formulations at all doses excepting ¹/₈ and ¹/₁₀th of LC₅₀ (9.1, 7.3 and 23.8, 19.0 g a.i/ha for pretilachlor and pendimethalin, respectively). Hatching success of the test specimens recorded 44.1 and 63.3% reduction from control for the highest applied dose (½ of LC₅₀) of pretilachlor and pendimethalin, respectively. Juveniles of Xenylla welchi exposed to ¹/₆, ¹/₈ and ¹/₁₀th LC₅₀ for pretilachlor (12.1, 9.1, 7.3 g a.i/ha) and ¹/₈ and ¹/₁₀th LC₅₀ for pendimethalin (23.8, 19.0 g ai/ha) survived and exhibited increased moulting frequency (7 moultings in 28 days in both the herbicide treatments) in comparison to control (8 moulting in 42 days). Test specimens required 26.0 ± 1.2 and 28.1 ± 2.1 days to attain sexual maturity exposed to pretilachlor and pendamethalin respectively which was significantly less than control (42 ± 2.6 days).

The 96 h LC(50) values of six insecticides were determined on a non-target epigeic earthworm Perionyx excavatus under laboratory conditions. Cypermethrin was found most toxic to P. excavatus (LC(50)-0.008 mg/kg), followed by endosulfan (LC(50)-0.03 mg/kg), carbaryl (LC(50)-6.07 mg/kg), chlorpyrifos (LC(50)-7.3 mg/kg), aldicarb (LC(50)-10.63 mg/kg) and monocrotophos (LC(50)-13.04 mg/kg). When these LC(50) values were compared with their respective recommended agricultural doses, aldicarb and carbaryl appeared more dangerous than other pesticides because of their lower LC(50) values than their respective recommended agricultural dose. Mean lethal time to cause 50% mortality at recommended agricultural dose (LT(50)) also indicated that aldicarb achieved the fastest LT(50) (26 h) followed by endosulfan (38 h) and carbaryl (44 h) indicating the danger of these pesticides to P. excavatus.

1. Dwarf egg layer (Narmada XL) dwarf broiler (DB) and normal bodied sib (NB) hens were studied under cyclic summer hot and dry heat stress of 21.1 to 45.5 degrees C for a period of 50 d. The genotype effect for egg production was significant (P less than 0.01). 2. N-XL and DB genotypes laid 12.1% more eggs than NB. Egg production declined by 3.17, 1.27 and 3.25% for a rise in temperature (maximum) of 1 degree C for N-XL, DB and NB genotypes respectively. 3. Egg production in Narmada XL declined by 42% compared to 25% in the dwarf broilers. The regression coefficients differed significantly. 4. For polygenically identical DB and NB broiler breeder hens the heat stressor significantly reduced egg production 1.98% more in the NB genotype compared with DB with a 1 degree C rise in temperature. 5. Mortality was less in the N-XL as compared to DB, but NB hens showed 11.7% more mortality than dwarfs.

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