Development of mass trapping technique for control of brinjal shoot and fruit borer, Leucinodes orbonalis (Lepidoptera: Pyralidae)

Abstract

Locally-produced clear plastic water traps (12 cm x 14 cm base and 21 cm height) were optimized for use in large-scale mass trapping trials for control of brinjal fruit and shoot borer, Leucinodes orbonalis Guenée. Changing the shape (square and triangular) and number (two and four) of entry holes in the water trap had no significant effect on trap catch. Significantly more male moths were caught in traps treated with water containing powdered detergent than liquid detergent, light gear oil or insecticide. All water traps tested caught significantly higher numbers of moths than sticky delta traps with open sides under farmers' field conditions. Trap catches per 100 m2 were found to increase with increasing number of traps from 3 to 6 but the difference in catch between 4 and 6 traps per 100 m2 was not significant. Two small-scale replicated integrated pest management (IPM) trials were conducted consisting of the optimized water trap placed out with 10 m spacing (4 per 100 m2) and infested shoots pruned and destroyed. The first season trial had two treatments, IPM and farmers' practice in which farmers applied insecticide every two days in the peak harvest period. Overall, the percentage of healthy fruit and yields in both treatments were comparable at 53.8 and 49.6% and 20 and 19.4 tonnes per ha in the IPM and farmers' practice plots respectively. However, the initial infestations in the IPM plots (68%) were significantly higher than in farmers' practice plots (16%) due to the proximity of the nurseries used for the IPM plots to stacks of brinjal crop residues from the previous season that acted as a source of infestation. The second season's trials contained a third treatment in which IPM and farmers' practice were combined. The percent total healthy fruits harvested were 46.1, 58.6 and 69.1% respectively for the farmers' practice, farmers' practice plus IPM and IPM alone. Averaged total fruit yields were approximately 12 tonnes per ha for the farmers' practice plots and 30 tonnes per ha for each of the IPM-treated plots. The IPM plot had significantly fewer infested fruit than the IPM plus farmers practice plots and this was attributed to the activity of the larval parasitoid Trathala flavo-orbitalis (Cameron) that was suppressed in trial plots treated with insecticides.

Sex Pheromones and Their Impact on Pest Management

“…Insecticides appear to be largely ineffective for control of L. orbonalis, because of protection offered by the fruit itself and because of insecticide resistance. A pheromone-based mass trapping strategy has been developed, from optimization of the pheromone blend and dose, trap design, and placement to field implementation (Cork et al 2001(Cork et al , 2003(Cork et al , 2005a. Mass trapping, without the use of insecticides, has led to a 50% and higher increase in marketable fruit, which has been attributed to the combined effects of mass trapping and enhanced impact of natural enemies.…”

Soil functions and ecosystem services in conventional, conservation, and integrated agricultural systems. A review

“…Additionally, the shading effect provided by the crop residue prevents weed germination [3] (Sarajuoghi et al 2012). At the same time, it also provides habitats for pests, exacerbating risk of their infestation [1] (Cork et al 2005;Govaerts et al 2007;IARI 2012). Still, the residue cover protects the ground surface and provides organic materials for the soil, improving overall soil quality [3], efficiently controlling soil erosion [3] (Lal and Pimentel 2009), and augmenting soil organic carbon stock [3] (Dendooven et al 2012).…”

“…Nevertheless, the ground surface exposure has been reported to increase soil temperature during the early growing season, increasing weed infestation [1] (Sarajuoghi et al 2012). Still, the absence of crop residue negates potential habitats for pests, decreasing their density and activity [3] (Cork et al 2005;IARI 2012). However, the residue removal lowers the protection of the ground surface from the raindrop splash impact and reduces the input of organic matter into the soil, lessening the overall soil quality (Dendooven et al 2012).…”

“…However, the concept of full conservation and low-impact practices can impose serious limitations in terms of soil quality and fertility and agroecosystem functioning and health. For example, conservation tillage may increase water deficiency for crops in drought years (Vyn et al 2013), entire retention of crop residue might boost pest infestation (Cork et al 2005), organic nutrient management can augment risk of off-site water source contamination (Flores et al 2012), and nonchemical pest management presents high risk of crop loss due to pest infestation (Pretty and Bharucha 2015).…”

Biorational insecticides in pest management

“…The most widely used attractants in monitoring systems are sex pheromones to monitor, 96,97) aggregation pheromones to monitor coleopteran species, 98,99) and host plant odors for dipteran species. 100) Although in the vast majority of cases a good correlation between catches and level of damage has been noticed, [101][102][103] sometimes the number of adults caught in traps was not correlated with the number of eggs laid and larvae found in plants.…”