Formulations mating disruption

Pheromone releaser distributions and/or point-source release rates have pronounced effects on the disruption of trap captures of spruce budworm (39). Small field plot studies with hand-placed releasers in moderate- to-high density budworm populations indicate an increase in trap disruption as the point sources of the synthetic pheromone are increased in release rate and decreased in number per unit area (Fig. 1). Identical pheromone dosages per plot were present in each treatment. Optimizing the releaser spacing and point-source release rate is therefore important and implies the need for a formulation re-design. This effect of releaser distribution and point-source release rate on trap disruption and mating disruption has been demonstrated in several insect species (40). 

A thorough understanding of the release performance of a controlled-release system under field conditions is essential, in order to have confidence that measurements of mating disruption (or trap capture) are due to biological effects of pheromone treatments and not formulation effects. 

Development Administration and ICI Ltd. have been involved In a collaborative project to develop microencapsulated formulations of lepidopterous sex pheromones for control of insect pests by mating disruption. 

Dlsparlure has also been used in mating disruption experiments since the early 1970 s and many of these experiments have demonstrated that mating of tethered females could be reduced by 90% or better in plots treated with controlled-release formulations of 20-50 g of racemic lure per hectare (12). One successful dlsparlure formulation for aerial application has been the laminate dispenser chopped into small flakes and coated with adhesive a special apparatus has been described for the application of these flakes (see later chapters in this symposium by Plimmer et al. and Kydoneieus et al.). Based on the release data obtained with dispensers, the small flakes, which have a high amount of perimeter or edge relative to their surface area, whould be expected to lose lure at a faster rate than larger dispensers made of the same laminate. 

Typical formulations and technology pertaining to mating-disruptant products developed by Hereon for the above insects are discussed below under the following three headings ... 

The behavior of two other formulations, microcapsules and small plastic laminate flakes, containing tetradecenol formate, were compared in applictions to plots of mature corn at Beltsville, in August 1980. (8) The Z-9-tetradecen-1-ol formate (TDF) is a mating disruptant, rather than a true pheromone, of the Heliothis species of moths. It was selected in these experiments because reliable analytical methods were available (9) and its behavior was expected to be similar to that of the actual pheromones, whose chemical structures and properties are also similar. The two formulations were polyurea-polyamide microcapsules 5-microns in diameter supplied by ICI at Bracknell, Berkshire, England, and a small (3 mm side) plastic laminate formulation supplied by the Herculite Corporation of York, PA. The microcapsules were applied at 300 g of TDF per hectare and the flakes at 285 g/h. Both formulations were applied by air to mature corn 240-270 cm in height in clear, hot weather with a daily maximum temperature of 39°C. 

Figure 1. Response of western pine shoot borer males to pheromone-baited traps in plots treated with different mating-disruption formulations and an untreated check plot. Key check (Q) 10 g pheromone in 20,000 flakes/ha (ffl) and 5 g pheromone in 25 strips/ha (ffl...

Then, the first EPA-registered mating disruption formulation, the Conrel hollow fibers, was developed in 1978. It used hollow microfibers ca. 2 cm in length. These fibers were distributed over cotton fields by using airplanes equipped with... 

It had routinely been assumed that successful mating disruption can only occur if the majority of females in a population are prevented from mating after the application of a mating disruption formulation. In reality, the females abilities to... 

Ilichev, A.L. Stelinski, L.L. Williams, D.G. Gut, L.J. Sprayable microencapsulated sex pheromone formulation for mating disruption of oriental fruit moth (Lepidoptera Tortricidae) in Australian peach and pear orchards. Journal of Economic Entomology 99(6), 2048-2054, 2006. 

Plimmer et al emphasize the need for effective formulations, and discuss disparlure formulations and strategies of applications 565, 566), They agree with Cameron (see above) We [Agricultural Research Service] have considerable investment in this research and it is continuing. However, it would be a mistake to oversell until we have done much more homework. I would like to be able to define precisely and reproducibly where and when mating disruption will succeed and whether it can be effectively combined with insecticide treatment at the larval state (for Lepidoptera). Our formulations need much development before we can be sure of their economy and reproducibility. Plimmer also notes (567) that even the basic question of responses to the enantiomers of disparlure still needs to be resolved. 

The sex attractant of several tick species have been identified, but only three examples of attempts to apply the attractant have come to our attention. Sonenshine has demonstrated (620) mating disruption by dusting a tick-infested dog with a microencapsulated formulation of the pheromone, 2,6-dichlorophenol the ticks used were the dog tick, Dermacentor variabilis, and the Rocky Mountain wood tick, Dermacentor andersoni. Gladney (621) applied a mixture of pesticide and male extract to a shaved area on the shoulders of cattle and found that the Gulf Coast tick (Amblyoma maculatwn) could be attracted to the spots and killed... 

SPLAT formulations have been developed to release a variety of compounds, including sex pheromones, kairomones, attractants, phagostimulants, and insecticides. Several mating disruption and attract-and-kill formulations are commercially available. SPLAT Verb and SPLAT AGP Repel represent our first successful attempts at developing repellent formulations and will be registered and marketed in the United States. 

The racemic form is as effective as the (+) enantiomer for disrupting mating. This technique for population suppression has been evaluated in experiments to compare the effects of formulation, dose rate and population density on its efficacy. In light infestations, gypsy moth mating is effectively suppressed. Microcapsules, laminated polymeric "flakes" and hollow fibers were compared as controlled-release formulations. 

Microencapsulated and hollow fiber formulations of the pheromone were shown to disrupt mating of both the RBLR and the GBM (578). However attempts to disrupt mating for the complex of moth pests were less successful improved formulations with better control of release rates of individual components are needed. Tumlinson et al. (579) and Roelofs (580) have dealt with the problems involved in manipulating complexes of insect pests. Roelofs and Card6 (21) have analyzed communication systems and their disruption by pheromones and para-pheromones. 

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