Impact of a synthetic insecticide and plant extracts on Aphis craccivora (Hemiptera: Aphididae) and coccinellid species in common beans

Bean crop is attacked by several phytophagous insects, affecting its production and causing losses to farmers. Among the insects considered as bean crop pests, aphids can cause economic damage by continuously sucking the plant sap throughout crop development. Thus, this study aimed to evaluate the control of Aphis craccivora on bean crop with insecticides and its effect on the presence of ladybugs. The tested products were: 1) imidacloprid + bifenthrin; 2) neem extract; 3) d-limonene, and, as a control treatment, water was applied. Insect mortality and the presence of ladybugs were checked every three days until harvest. There was a reduction in the population of aphids after the application of the products for up to 27 days. The presence of ladybugs was higher in the control treatment than in the treatments with insecticides. Thus, the tested products were considered potential in the control of A. craccivora. However, they also negatively affected the presence of coccinellids.

INSECTICIDAL EVALUATION OF AQUEOUS EXTRACT OF INDIGENOUS PLANTS IN COMPARISON WITH SYNTHETIC INSECTICIDE FOR THE MANAGMENENT OF THRIPS Scirtothrips dorsalis (Thysnaoptera; Thripidae) IN TOMATO CROP

Insecticidal evaluation of aqueous extracts of indigenous plant extracts in comparison with synthetic insecticide against Thrips (Scirotothrips dorsalis) on tomato was conducted under natural field condition during spring 2019. Experiment consists of 8 treatments (neem extract, tobacco extract, garlic extract, datura extract, lantana extract, eucalyptus extract, flonicamid (synthetic insecticide) and control following RCB Design with 3 replications. Treatments were applied thrice after 15 days interval. Results revealed that the three times application of the tested treatments showed varying toxicity against S. dorsalis 24, 48, 72 hours and 7 days after spray applications while ladybird beetle and green lacewing were also significantly affected when recorded 7 days after spray application. However, Flonicamid 50%WG proved to be the most effective till 7th and had lowest pest population followed datura and neem extract. neem extract in all the three spray application . Garlic and eucalyptus also produced significant results compared to control. Neem, tobacco, datura and flonicamid were found to be comparatively more hazardous to ladybird beetle and green lacewing population compared to eucalyptus, garlic and lantana to in all three spray application. Tomato yield was highest with flonicamid (12533 kg/ha) followed by datura and neem (11810 kg/ha and 11300 kg/ha) respectively, while lowest (8133 kg/ha) in control. It is concluded from the current research that flonicamid performed better against S. dorsalis but comparatively more hazardous to natural enemies however lantana, garlic and eucalyptus extract showed better result against S. dorsalis and comparatively safe towards natural enemies thus recommended to be incorporated in IPM program.

Biodegradation of DDT by Co-cultures of Pleurotus eryngii and Pseudomonas aeruginosa

Dichloro-diphenyl-trichloroethane (DDT) is a synthetic insecticide that widely used around the world, which has a negative effect on human health and the environment. The objective of this research was to investigate the ability of bacterium Pseudomonas aeruginosa in co-culturing with white-rot fungus Pleurotus eryngii to degrade DDT. The various volume of P. aeruginosa (1 ml ≈ 1.5 x 109 CFU) were added into 10 ml of P. eryngii culture for a 7-days of incubation. Approximately 82% of degradation of DDT were obtained from co-cultures with the adjunct of 10 ml of P. aeruginosa during the 7-day incubation period, which had the best ratio of optimization of 0.57. The confrontational assay showed that P. aeruginosa gave no effect on the growth of P. eryngii (0.39 cm/day). DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene) were detected as metabolic products from the DDT degradation by co-cultures bacterium P. aeruginosa and fungus P. eryngii. This study indicated that bacterium P. aeruginosa can be used to enhance DDT degradation by whire-rot fungus P. eryngii.

Arboreal arthropod assemblages in chili pepper with different mulches and pest managements in freshwater swamps of South Sumatra, Indonesia

Herlinda S, Tricahyati T, Irsan C, Karenina T, Hasbi, Suparman, Lakitan B, Anggraini E, Arsi. 2021. Arboreal arthropod assemblages in chili pepper with different mulches and pest managements in freshwater swamps of South Sumatra, Indonesia. Biodiversitas 22: 3057-3066. In the center of freshwater swamps in South Sumatra, three different chili cultivation practices are generally found, namely differences in mulch and pest management that can affect arthropod assemblages. The effect of mulches and pest management on arboreal arthropod assemblages specific to chili production centers in the freshwater swamps of South Sumatra has never been investigated. This study aimed to observe arboreal arthropod assemblages in chili with different mulches and pest management. Arboreal arthropods were sampled using sweep nets in three locations with plots treated with leaf litter mulch and bioinsecticide, plastic mulch and synthetic insecticide, and weedy plot without mulch with synthetic insecticide. The species number of arboreal arthropods found was 28 species of Arachnids and 23 species of Insects, and consisting of 6 families of the Arachnids and 25 families of Insects. The abundance of arboreal arthropods was 65.60 individuals/5 nets per observation. In the chili field without mulch but with the insecticide, the species biodiversity and abundance of arboreal predatory arthropods were the highest. In contrast, in the chili field, that applied with synthetic insecticides and plastic mulch, the abundance of arboreal predatory arthropods was the lowest. The herbivorous insect populations in chili with plastic mulch and synthetic insecticides and the chili with the leaf litter mulch were higher than those in the chili without mulch. In the chili with the leaf litter mulch and bioinsecticide, the species number and abundance of the spiders were the highest compared to the other chili fields. The weedy chili field without mulch and chili with the leaf litter mulch has proved ideal habitats for the arboreal predatory arthropods.

Effectiveness Test of Piper methysticum Extract Against Crocidolomia pavonana larvae

Application synthetic insecticide with high frequency and continuously can give to negative impact. Alternative control which secures is botanical insecticide. This research aimed to effectiveness tests of P. methysticum plant against C. pavonana larvae using root and leaves this plant. The tested insecticide activity including mortality and feeding inhibition tests. The extract was tested at five concentration levels and repeated five times. The results showed that P. methysticum root extract was able to cause C. pavonana larvae mortality of 94% with a concentration of 419.7 gram/100 ml in water meanwhile, the testing using leaves extract causes mortality 98% from concentration 342 gr/100 ml in water. The feeding inhibition test showed the P. methysticum roots extract give effect with very weak criteria at some concentrations used a no choice method while Leaves extract P. methysticum does not show feeding inhibition.

Evaluation of two phyto powder combinations (Azadiracta indica and Zingiber officinale) and a synthetic insecticide (Primiphos methyl powder) in the control of cowpea weevil Callosobrucus maculatus (Fab.)

Cowpea (Vigna unguiculata L. walp) is one of the most important leguminous crops that are widely grown throughout the tropics. The aim of the study is to evaluate the combination of two botanical powders and a synthetic insecticide in the control of cowpea weevil (Callosobruchus maculatus) on stored cowpea grain. The botanical powders were admixed with the cowpea grain at a combination of 3:7, 7:3 and 5:5 per 50g of beans while the primiphos methyl powder was admixed at 0.25g per 50g of cowpea. In the control, no treatment was used. The experimental design adopted for the experiment was Complete Randomized Design (CRD) and each treatment was replicated four times for each experiment. Twenty (20) adults of C. maculatus unsexed (taken from stock culture kept in the laboratory) were introduced into each vial including the control and were covered with muslin cloth held tightly in place with rubber band to prevent the weevils from escaping. The experiments were monitored for 72 hours. The results showed that the plant powders and primiphos methyl powder were good grain protectants. The highest mortality recorded was in primiphos methyl powder (78) followed by the combination of Azadirachta indica and Zingiber officinale powder at the ratio of 5:5 (76), 7:3 (68) while the least was 3:7 which recorded 62. The mean mortality of C. maculatus caused by primiphos methyl powder (6.50), was significantly (P<0.05) different from the untreated control (0.00), but was not statistically different from the combination of Azadirachta indica and Zingiber officinale in the ratio of 5 to 5, but the combinations of A. indica and Z. officinale in the ratio of 3:7 and 7:3 were significantly different. The study suggests that botanicals should be incorporated into grain protection as alternatives to chemical insecticides in the control of C. maculatus in cowpea grain during storage.

Comparative Efficacy of Jatropha curcas L. Seed Powder for the Control of Callosobruchus subinnotatus (Pic) on Stored Bambaranut, Vigna subterranea (L.) Verdcourt

The study was to assess insecticidal effectiveness of Jatropha curcas L. seed powder on Callosobruchus subinnotatus (Pic) infesting stored bambaranut, Vigna subterranea (L.) Verdcourt. The experiment was laid out in a factorial design of 4×2 levels (seed powder at the rates of 0.0, 0.5. 1.0 and 1.5 g, with and without addition of the synthetic insecticide at 0.01 g/20 g bambaranut seed) and laid out in a completely randomized design, in three replicates. Results obtained showed lowest oviposition, progeny emergence and seed damage (5.33, 1.58 and 1.83, respectively) in bambaranut seeds admixed with 1.0 g of the seed. Although, statistically similar to all other treatments, it was significantly (P≤0.001) better than the control treatment in which 33.83 eggs were laid and 24.08 adults emerged from 22.92 emergence holes. In addition, at six (6) days after treatment, highest adult mortality rate (99.17%) similar to that (99.17%) obtained in the synthetic insecticide was also recorded in seeds treated with 1.0 g seed powder. However, all other treatments were also significantly better than the control, in which 72.50% of the introduced bruchids died. Comparatively, lowest rate of seed damage (6.68%) and lasting effect was also obtained with the addition 1.0 g seed powder. In conclusion, appreciable level of protection on bambaranut seeds was achieved using seed powder of J. curcas. Therefore, it is recommended that for effective management of C. subinnotatus infesting bambaranut, farmers could use 5 Kg seed powder on 100 Kg bambaranut seeds.