Toxic and Antifeedant Effects of Different Pesticidal Plant Extracts against Beet Armyworm (<i>Spodoptera exigua</i>)

Abstract

The beet armyworm (BAW), Spodoptera exigua (Lepidoptera: Noctuidae) is a highly destructive pest of vegetables and field crops. Management of beet armyworm primarily relies on synthetic pesticides, which is threatening the beneficial community and environment. Most importantly, the BAW developed resistance to synthetic pesticides with making it difficult to manage. Therefore, alternative and environment-friendly pest management tactics are urgently required. The use of pesticidal plant extracts provides an effective way for a sustainable pest management program. To evaluate the use of pesticidal plant extracts against BAW, we selected six plant species (Lantana camara, Aloe vera, Azadirachta indica, Cymbopogon citratus, Nicotiana tabacum, and Ocimum basilicum) for initial screening experiment. Four out of six plant species such as A. indica, N. tabacum, C. citratus and O. basilicum showed promising mortality of more than 50%. Therefore, we selected these four plant extracts for the subsequent experiments. Through contact bioassay, A. indica showed high mortality 66.63%, followed by the N. tabacum 53.33%, at 10% w/v concentration. Similarly, N. tabacum showed the highest mortality rate, 66% at 10% w/v concentration, followed by the A. indica 46% through feeding bioassay. Furthermore, the feeding deterrence assay showed that C. citratus had a high antifeedant index (−50) followed by A. indica (−39), and N. tabacum (−28). In living plant assay, the N. tabacum extract showed a low mean damage score 3.6 on living cotton plant followed by C. citratus 4.5 and A. indica 5.5. Hence, extracts of three plant species provided promising results against the BAW, which can minimize the use of synthetic chemicals, particularly for small landholding farmers. Further studies are also required to evaluate the effects of these plant extract against BAW on cotton plants under field conditions to optimize the further use.

Multifaceted Impacts of Plant-Beneficial Pseudomonas spp. in Managing Various Plant Diseases and Crop Yield Improvement

“…5 The environmental protection and health issues of these harmful chemical materials have increased the necessity of searching for substitutions to control plant diseases and pests. 6 The application of biocontrol plantgrowth-promoting rhizobacteria (PGPR) has been proven to be ecofriendly and cost-effective and has a significant role in managing various diseases, as well as improving plant growth and productivity. 7 One group of very significant bacteria that has become a focal point of research on biological control of plant diseases is the genus Pseudomonas (ubiquitous, rod-shaped γ-proteobacteria and Gram-negative bacteria having polar flagella).…”

“…These synthetic fertilizers pose a severe threat to the soil biota by disturbing environmental nutrient cycles, disrupting the biological communities existing in the environment, and having adverse health consequences . The environmental protection and health issues of these harmful chemical materials have increased the necessity of searching for substitutions to control plant diseases and pests . The application of biocontrol plant-growth-promoting rhizobacteria (PGPR) has been proven to be ecofriendly and cost-effective and has a significant role in managing various diseases, as well as improving plant growth and productivity …”

“… 5 The environmental protection and health issues of these harmful chemical materials have increased the necessity of searching for substitutions to control plant diseases and pests. 6 The application of biocontrol plant-growth-promoting rhizobacteria (PGPR) has been proven to be ecofriendly and cost-effective and has a significant role in managing various diseases, as well as improving plant growth and productivity. 7 …”

Morphoanatomical and Physiological Adaptations of Triticum aestivum L. against Allelopathic Extract of Trianthema portulacastrum L. (Horse purslane)

“…7 Several biotic and abiotic factors cause low wheat yield; 8,9 among these, weed infestation is one of the main limiting biological constraints. 10 Almost 30,000 weed species have been recognized in the world, and out of these, 18,000 species can cause a significant loss to crop yield. 11 They are the main bottleneck in crop-growing systems as they compete for space, capture nutritional precious resources, and ultimately lead to a significant decrease in wheat crop production.…”

“…Several biotic and abiotic factors cause low wheat yield; , among these, weed infestation is one of the main limiting biological constraints . Almost 30,000 weed species have been recognized in the world, and out of these, 18,000 species can cause a significant loss to crop yield .…”