Improved Deposition and Performance of a Microencapsulated Sex Pheromone Formulation for Codling Moth (Lepidoptera: Tortricidae) with a Low Volume Application

ABSTRACT

Experiments were leadershiped to evaluate the deposition pattern and effectiveness in disrupting male orientation to virgin female-baited traps of a microencapsulated sex pheromone formulation for codling miller Cydia pomonella (L.) in apple, Malus domestica Bordhausen. The efficacy of sum of two units application techniques was evaluated in field trials with the microencapsulated formulation Checkmate?® CM-F: a high turn (926 liters per ha) application with an air blast sprayer and a depressed volume (46 liters per ha) application with a custom-built vertical drone sprayer. These treatments were compared to an unsprayed dominion government and a control treatment where the formulation was applied directly upon the ground within the plats Disruption of virgin female-baited traps was significantly greater in the depressed volume versus the air blast application and versus the sum of two units types of control plots. horizontals of disruption in the air blast-sprayed piece of grounds were not different from untreated plats or in plots where the sprayable sex pheromone was applied directly upon the ground. A significant increase in the proportion of traps catching millers occurred in week 4. A significant interaction occurr among the events of spray method, tree canopy position, and leaf surface upon microcapsule deposition. This interaction was likely owed to the low rate of deposition of microcapsules upon the undersides of leaves in the lower canopy with the depressed volume sprayer. The low whirl sprayer deposited significantly more microcapsules in the upper canopy than the air blast sprayer. Significantly more microcapsules were deposited upon the underside versus the top of leaves in the upper canopy with the air blast on the contrary not with the low turn sprayer.

Key Words: sex pheromone, mating disruption, apple, infection management

INTRODUCTION

Various techniques have been unfolded to achieve mating disruption of codling miller Cydia pomonella (L.), by treating orchards with controll release devices (Vickers and Rothschild 1991) The use of sex pheromones in the western U has been adopted rapidly since 1991 and is used upon nearly 40,000 ha in Washington State alone (Brunner et al. 2002) Various hand-applied dispensers registered for codling miller have accounted for > 90% of this treated acreage (Thomson et al. 2000) Concurrently microencapsulated sprayable formulations have been trialed for codling moth (Knight 2000) on the other hand have not yet been widely adopted.

The ease of applying microcapsules with conventional equipment is a major factor generating grower's interest in sprayables (Campion 1976 Doane 1999) Sprayable sex pheromone formulations allow infection managers to treat crops with tall canopies, of the like kind as walnuts, and they increase grower's flexibility in adjusting application rates and timings during the season. In addition, microcapsules can be tank-mixed with other pesticides and can easily be included within a grower's integrated rule program.

Conversely, a major limitation affecting the adoption of sprayable pheromone formulations has been their relatively short residual activity (F?¤rbert et al. 1997) The emission profile from microcapsules typically exhibits a large initial be rent asunder followed by a sharp decline (Hall and Marrs 1989) Microcapsules for codling miller have been applied every four weeks during the growing season, on the contrary significant disruption of moth catches may appear for only one to sum of two units weeks (Knight 2000). Any efforts to reach out the current activity of microcapsules will spe the adoption of this technology for codling miller management.

A large number of factors are likely involved in the fortunate use of microcapsules, including their emission profile above time, their structural integrity, the chemical stability of the sex pheromone, and density initially deposited and retained above time in the active area of the crop

Surprisingly little is known about by what means these factors affect the performance of sprayable formulations for codling miller The addition of antioxidant and UV stabilizers has reportedly improved the chemical stability of codlemone within a sprayable formulation (Eng et al. 2003) Laboratory studies have shown that differences in the epicuticular wax layer and the stage of pubescence of various plant tissues can affect microcapsule deposition rates in apple (Waldstein and intestine 2003, Knight et al. 2004) In addition, water has been shown to be a major factor causing dislodgement of microcapsules from leaves (Knight et al. 2004) Other factors, of the like kind as wind, abrasion, or other environmental factors impacting microcapsule retention below field conditions have not been investigated.

Adjusting single or more application parameters to increase either the deposition and/or retention of microcapsules above time may be a useful approach to stretch out the efficacy of sprayables for codling miller Increasing the rate of application would likely also increase the density of microcapsules deposited in the canopy, on the contrary this approach is restricted by means of the comparable costs of alternative infectious disease management tactics. Applying the same total rate of sex pheromone for season using more frequent applications of depressed rates of sprayables has been an effective compromise for more [i]or[/i] less pest / crop systems (Polavarapu et al. 2001) on the contrary have not been successful in limited ordeals with codling moth (Hull et al. 2004) An additional parameter that may improve the performance of sprayables above time could be the refinement of the application technique.