Impact of Biocide, Insecticides, Compost and Mineral Fertilizers Treatments on the Abundance of Parasitoid and Predator Insects in Rice Fields

Abstract

The present study was designed to investigate the effect of rice straw compost, recommended mineral fertilizers, Organic Insecticides and chemical Insecticides on the abundance pattern of natural enemies in rice ecosystems. To maximize rice productivity, rice growers tend to use chemical fertilizers and pesticides particularly to control different pest species, regardless of damage levels. Accordingly, rice fauna of natural enemies is severely impaired, leading to unbalanced rice ecosystems. The current investigation was carried out at the experimental farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh during 2016 and 2017 rice seasons. Using both D-Vac machine and pit-fall traps, parasitoids and predator insects were surveyed. Twelve hymenopterous parasitoid species were surveyed. Most of the parasitoid species were found belonging to Mymaridae, Trichogrammatidae and Braconidae. Twenty insect predator species, related to 13 families and seven orders, were identified, most of which are belonging to Coleoptera and Hymenoptera. Also this study aimed to surveying natural enemies (parasitoids and predator insects) and the effect of compost as an organic fertilizer on population densities of such beneficial insects. Although the application of insecticides successfully controlled insect pests, these chemicals have almost eradicated (more than 90 % reduction) the natural enemies. Biocide applications, especially Achook (Neem) and Tracer, achieved a considerable insect pest control, with population reductions of 33.30-57.32 and 10-46.01%, respectively. Unfortunately, the evaluated biocides induced mortalities to the considered natural enemies, but with too much less levels than did the insecticides. The current results indicate that the biocides could be applied to control rice insects in case of moderate insect infestations, with taking into consideration that they are not completely safe to the beneficial insects.

Salivazo Clastoptera achatina Germar (Hemiptera: Clastopteridae) en nogal Pecanero: Fluctuación poblacional, distribución y eficacia de insecticidas

“…100 L −1 de agua tuvo una efectividad biológica del 90% a las 72 h y 7 días después de la aplicación, este insecticida se ha reportado como de bajo impacto sobre depredadores y parasitoides, lo que lo convierte en una buena opción para los programas de manejo integrado de plagas y manejo de poblaciones resistentes (Pazini et al 2016, Stecca et al 2017, Mora et al 2018. En tanto que Spinetoram presentó efectividad constante del 100% para el control de C. achatina a las 72 h y 7 días después de su aplicación, pero sus efectos sobre insectos no objetivo parasitoides y depredadores puede variar según la especie, ya que algunos autores reportan mortalidades de moderadas a altas en parasitoides (García y Tarango 2011, Sheikh et al 2018, mientras que en depredadores puede ser baja o nula como en Chrysopa sp. y coccinélidos, los cuales son importantes para el control de C. achatina y otras plagas del nogal (Aguilar 2014, Visnupriya y Muthukrishnan 2017, Slusher et al 2021.…”

The Insect Pests, the Associated Predatory Insects and Prevailing Spiders in Rice Fields

“…The predatory insects are effective in regulating the pest population and accordingly, they should be conserved (Mesbah and Sherief 1999, Hendawy et al 2005, El-Sheikh et al 2018. surveyed aquatic insect predators and terrestrials insect predators as effective bio control agents in paddy fields.…”