BackgroundEnergy flows in most food chains in the agroecosystem are crowned with beneficial natural enemies including different species of predatory and parasitic insects, birds and animals. They are utilized in organic and IPM cotton production to replace the conventional insecticides usually applied in cotton production.ResultsNatural populations of six coccinellids, five staphylinids and two carabids (Coleoptera), three anthocorids and three reduviids (Heteroptera), five syrphids (Diptera, three labidurids (Dermaptera), two chrysopids (Neuroptera) and one thripid (Thysanoptera) species were manipulated in Egyptian clover to aggregate in seed production stripes (stripe technique) adjacent to and across the cotton fields during April-May, 2022. These 30 predatory species represent 112 energy flow routes in food chains preying on tetranychid mites, aphids, thrips, whiteflies and cotton leaf worm attacking cotton plants during vegetative growth stage beginning from April to May 2022. High populations of these predators develop along the clover season (November-May) on different pests where no insecticide applications occur. They aggregate in the flowering clover stripes left for seed production feeding on nectar, pollens and remaining pests. By dryness of the clover stripes, populations of all these predatory species abandon the clover, migrating outwards into the adjacent cotton or corn fields showing an excellent high protection against cotton pests suppressing their populations far away under the level of economic threshold damage during vegetative growth stage. Dressing cotton seeds with Bacillus amyloliquefaciens as antagonist protects the seedlings from soil-borne diseases. Insect pheromone traps detected the first appearance of the pink bollworm, Pectinophora gossypiella (Saund.) moths, the cotton bolls are attacked also by the spiny bollworm, Earias insulana (Boisd.). The egg parasitoid Trichogramma evanescens (West.) was released in 6 successive releases to guide the energy flow in favor of the parasitoid by getting it from egg contents of these two pests, which resulted in high protection of cotton bolls. This study aims better understanding of biodiversity and the routes of energy flow among the complex net of food chains governing the bio-dynamics in the Egyptian agroecosystem, which enabled the development of the present strategy to completely abandon application of the conventional insecticides and chemical fertilization for organic cotton production in Egypt.ConclusionThe study is an approach contributing to improvement of the agroecosystem and production of healthy crops.

The use of plant growth promoting rhizobacteria (PGPRs) to improve crop growth under salt stress is gaining attention in recent years. In this study, we evaluated the potential of Bacillus amyloliquefaciens strain Q1 to mitigate salt stress in barley. Barley seedlings were inoculated without (-) or with (+) Q1 and then subjected to four salt levels (0-320 mM) to assess the changes in plant growth, photosynthetic attributes, ion homeostasis, and antioxidant capacity. Our results revealed that the slight salt stress (80 mM) caused little damage to plant growth and physiological processes of barley seedlings, indicating the potential of barley for crop production in saline soils equal to or less than this salt level. However, the moderate (160 mM)- or severe (320 mM)-level salt stress considerably reduced the plant growth of barley seedlings, because of the inhibition of photosynthetic capacity and disruption of Na+/K+ homeostasis. The inoculation with Q1 notably ameliorated these detrimental effects of salt stress, and its efficacy was more predominant at the severe salt level. Moreover, Q1 significantly enhanced the activities of antioxidant enzymes in barley at the severe salt level, but not at the slight or moderate salt level. Taken together, it is concluded that Q1 has limited promoting effect on barley under the normal growth condition, whereas it is capable to help barley maintain much better growth and performance under salt stress, especially at the severe level. Our study has expanded the list of PGPR resources for sustainable utilization of saline land.

Background: Sclerotium bataticola, a soil-born fungus, is responsible for charcoal rot in a variety of plants. It is also responsible for causing substantial damage to a wide range of horticultural crops around the world. Methods: Fifteen different Bacillus isolates were isolated and evaluated for their ability to inhibit S. batatacola's growth. The promising bacterial isolate was molecularly identified using NCBI-Blast and phylogenetic tree analysis of the 16S rRNA gene. Batch fermentation was performed in a stirred tank bioreactor to maximize culture biomass and secondary metabolite synthesis. Gas chromatography-mass spectrometry was used to discover secondary metabolite compounds. Results: The KSAS6 isolate was the most effective for inhibiting the fungal growth of mycelial cells, with a 48.2% inhibition percentage. The probable biocontrol agent, B. amyloliquefaciens strain KSAS6, was identified and recorded in GenBank under the accession number PQ271636. The culture biomass and secondary metabolites were maximized by the batch fermentation technique, reaching the highest achievable level of 2.1 g L-1 at 11 hours. This was accomplished while maintaining a steady specific growth rate (mu) of 0.13 h(-1). Based on the observations, the biomass yield coefficient was found to be 0.37 g cells/g glucose. Among the 21 secondary metabolite compounds identified in GC-MS analysis, diisooctyl phthalate was the highest compound (43.31%). Conclusion: The strain of rhizobacterium B. amyloliquefaciens known as KSAS6 can inhibit the growth of S. bataticola, which makes it a promising candidate for the biocontrol of fungal infections in plants.