weevil insecticides on 95% of the field. Neighboring check fields
treated conventionally required 10 to 13 applications for weevil
control compared to 0 to 4 full-field applications for the cotton
protected by the trap crop zones (Table 1).

 One of the most intriguing methods currently used in pest
management is the mating disruption technique. In this method,
slow release formulations are used to permeate the atmosphere
with the sex pheromone. The treatment disrupts the normal
mating behavior in several possible ways. Pheromone released
from the microtubes may mask the natural pheromone trails of
the female moths so that their trails are not detectable. The
microtubes may also outcompete with the females because there
are many more distinct sites of the synthetic pheromone and each
microtube is continuously releasing pheromone at a much higher
rate than the females. Thus, males flying through the field in


search of mating partners are attracted by the stronger false trails
of the microtubes rather than the true females.
 Mating disruption has been most intensively investigated for
control of the pin bollworm on cotton in various countries. In
1979 a large-scale test was conducted by the government of India
(Pawar et al., 1981). Approximately 80 growers with an average
field size of 4 ha each participated in the trial. Populations of the
pink bollworm were very heavy in this region partly due to the
practice of storing cotton plants for fuel. Pink bollworms emerg-
ing from old bolls in these storage piles move back into the new
crop after boll formation begins. In spite of heavy population
pressure, boll infestation was significantly reduced in the treated
block of fields-only 59% of the infestation found in the conven-
tional practice block (Fig. 1). Seed cotton yields were increased by
as much as 33.7% in the mating disruption cotton compared to
the conventionally treated cotton.


 TABLE 1. Comparison of pheromone trap crop technique and conventional insecticide program.


 Average number of
 Seasonal Average weevil insecticide
Treatment --damaged squares applications required

Pheromone trap crop 5,9 1

Convent onal practice 11.5 10,75


1/Azinphos-methyl or methyl parathion at ,28/ha



 FIG. 1 Boll infestation from pink bollworm in pheromone treated fields and in the conventional practice fields near Bucho Khurd, India.




 50 BUCHO KHURD VILLAGE, PUNJAB, INDIA, 1979

 45

 40 PHEROMONE TREATMENT
 /, /
 35 ---- CONVENTIONAL PRACTICE TREATMENT /
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