Assessment of Insecticidal Effect of Some Botanical Extracts against Culex pipiens and Musca domestica Larvae and Adults

Abstract

Throughout history till nowadays Musca domestica is still a worldwide problem. It plays a prominent role as a vector of various human pathogens. Culex pipiens is a worldwide mosquito causing nuisance and transmitting many dangerous diseases. With the emergence of resistance to many insecticides, control of these two synanthropic insects is becoming more difficult. Botanical insecticides are one of the successful alternatives as recorded by studies on plant-insect interaction. They are new environmentally safe, target-specific insecticides. Therefore, this study aimed at evaluation of the insecticidal efficiency of five plant extracts; Anethum graveolens, Mentha cervina, Ocimum basilicum, Thymus vulgaris and Coriandrum sativum on Culex pipiens and Musca domestica larvae and adults, applying three different bioassay techniques. These ethnobotanical culinary plants were selected being cheap and available in egyptian market. In CDC bottle bioassay for Culex pipiens adults, basil was found to be the most effective extract (LC50: .330 g /L), while the least effective is dill (LC50: .495 g/L). For Musca domestica adults, basil was the most effective extract (LC50: 1.074g/L), while mint is the least effective (LC50: 1.198 g/L). Fumigation bioassay was performed on both adults. For Culex pipiens adults, basil has the highest toxicity index (LC50: 22.937g/L) and dill has the lowest toxicity (LC50: 37.124g/L). In housefly adults thyme was the most effective extract (LC50: 33.339g/L), while dill is the least effective (LC50: 61.147 g/L). Feeding toxicity of Culex pipiens adults revealed that basil has the highest toxicity (LC50: 13.148 g/L) and mint has the lowest toxicity (LC50: 30.715 g/L). Feeding technique of Musca domestica adults revealed that coriander has the highest toxicity (LC50: 22.673 g/L) and basil has the lowest toxicity (LC50: 35.078g/L). In larval fumigation of Culex pipiens, dill has the highest toxicity (LC50: 24.390 g/L) and basil has the lowest toxicity (LC50: 27.617 g/L) while for Musca domestica larvae, coriander has the highest toxicity (LC50 29.521 g/L) and dill has the lowest toxicity (LC50: 59.627 g/L). Feeding toxicity of Culex pipiens larvae revealed that mint was the most effective extract (LC50: .049g/L), while the least effective was coriander (LC50: .073 g/L). For Musca domestica larvae, basil has the highest toxicity (LC50: .749g/L) and thyme has the lowest toxicity (LC50: 1.624g/L). Dipping technique of Musca domestica larvae revealed that basil has the highest toxicity (LC50: 32.643 g/L) and mint has the lowest toxicity (LC50: 61.430g/L). The plants selected showed a promising potentiality to be used as green insecticides in controlling both Culex pipiens and Musca domestica, with basil extract providing the highest toxicity index in six out eleven tested models. Therefore, synergetic effect of plants' mixture and their integration with other eco-friendly control strategies are required. Industrialization, commercialization and creation of market opportunities for aromatic plants application as a part of insecticides industry are mandatory to help in our economic development.