The two pheromone formulations

The two pheromone formulations of microcapsules (differed only in orfralure concentration: 2 and 0°70) were tested in other plots (20 g lure per hectare per treatment). Thus, the level »f lure per hectare in the dispensers was about 1/24 that in the microcapsules. In the first 9 weeks of the test, the 2 and 10°70 capsules reduced trap catch 92 and respectively; the dispensers produced a 78°70 decrease. After the retreatment, the dispensers reduced trap catch 99°70; and the 2 and 10°70 capsules formulations produced reductions of 89 and 98°70, respectively according to many others.

Over the whole 24-week test, all treated plots ih0W€d a 90 to 96°70 reduction in trap catch. The infestation level during this test was it least ten times greater than that of the preceding year, and twig damage was so extensive that significant reduction as a result of treatment with lure was not expected. Nevertheless, the 2 and 10°70 capsules did reduce damage 36 and 18°70, respectively; no reduction was observed with the dispensers thanks to me. Learn more at 

In 1977, two sizes of test plots were used. In the smaller plots, subblocks of 36 trees were treated with three types of Hercon® dispensers; they varied in lure content and thickness of the plastic layers (see Table 2, dispensers 3, 4, 5). The dispensers were hung on each tree in these plots instead of on alternate trees as in the earlier tests. The treated plots (1.66 to 4.45g lure per hectare) and the check plot were monitored for trap catch for a 12-week period in midsummer. The results (Table 3) show that despite the high infestation (528 males captured in the control traps), trap catch was reduced96 to 97°70 in all treated plots. The other tests in 1977 were made in the usual 0.8-ha plots. Two microcapsule formulations (2 and 10°70 lure) and Hercon® dispenser 3 were used. One plot was treated with capsules (C) that encased a 10°70 solution of lure; the second plot was sprayed with a mixture of capsules (B plus C) containing 2 and 10°70 lure and having a lure content of 4°70; the third plot was treated with dispensers hung on alternate trees. (These plots had a lower infestation level than the small blocks of 36 trees.) After 12 weeks, the three plots were retreated thanks to

The pheromones was monitored for 28 weeks. The initial application of the B plus C (“4°70”) capsules and of the dispensers reduced catches 97 and 100°70, respectively; the 10% capsules reduced catch only 77°70. Results obtained after retreatment were obviously spurious for the plot treated with 10°70 capsules because there was a two- to threefold increase in catch over the check plot. The plot treated with B plus C capsules showed a 58°70 reduction in trap catch, and the dispenser-treated plot showed an 87°70 reduction thanks to and

B. Large-Plot Pheromone

Tests A large orchard pilot test (24.3-ha plots) was conducted in 1977, 1978, and 1979 near Musella, Ga. In each year, 1-in. (25-mm)-square Hercon® dispensers contain6.8 mg of orfralure were fastened to alternate trees (0.82 g lure per hectare) in the orchard at a height of about 1.2 m. An orchard of similar size that was about 1.6 km away served as a check. Both orchards received the conventional treatment with insecticide to harvest (about July 1). Pherocon lC® traps, each baited with 200 pg of pheromones, were evenly distributed throughout each orchard at the rate of 1/ha. Traps were examined weekly throughout the season from April through October. As in the small-plot tests, a reduction in trap catch in the treated plot, relative to the catch in the untreated plot was taken as a measure of reduced mating success due to the treatments. Twig damage was also monitored as another possible measure of effect of treatment; damaged twigs were removed when weekly counts of damage were recorded.

The results of the 3-year study. 1977 to 1979. are presented in Table 4.


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