Relationship Between Pheromone-trap Catches and Sunset Temperatures During the Spring Flight to Codling Moth (Lepidoptera: Olethreutidae) Infestations in Walnuts

1986 ◽  
Vol 79 (2) ◽  
pp. 444-446 ◽  
Author(s):  
P. S. McNally ◽  
R. van Steenwyk
1980 ◽  
Vol 112 (7) ◽  
pp. 655-663 ◽  
Author(s):  
Helmut Riedl

AbstractPheromone trap density is one factor which influences the magnitude of catch and therefore, should be standardized in a monitoring program. Trap catch increased with the area served by a trap, but reached a plateau when the trap density fell below one trap per 7 ha. From these data a quadratic regression was developed which relates the relative increase in trap catch to trap area. This relationship can be used to compare monitoring data obtained with different trap densities.The number of moths previously caught in a sticky trap can affect its future performance. In the Pherocon® 2 trap catches began to decline after a cumulative total of 20 to 30 moths and in the Pherocon 1CP after 50 to 70 moths. The catch totals causing a drop in trapping efficiency were correlated with the size of the adhesive catch surface. The cause for the loss in trapping efficiency appeared to be physical deterioration of the adhesive due to moth scales, other insect parts, or dust rather than an olfactory repellent factor. Trapping efficiency was restored by thoroughly stirring the soiled adhesive. Standard maintenance procedures should be followed to keep the adhesive quality of the catch surface constant and thereby prevent a reduction in catches. Tests with two pheromone dispensers, the Codlemone® rubber septum and the Conrel® microfibres, indicated that both are effective for at least 6 weeks. Codlemone septa resulted in higher catches during the first week of field use. During subsequent weeks there was no difference in attractiveness between the two pheromone lures.


1974 ◽  
Vol 106 (5) ◽  
pp. 525-537 ◽  
Author(s):  
H. Riedl ◽  
B. A. Croft

AbstractA sex pheromone trap was studied as a quantitative sampling device in a biological monitoring scheme for codling moth populations in Michigan apple orchards. Factors influencing trap efficiency and the relationship of trap catch to adult moth density and the overall seasonal dynamics of L. pomonella are considered.By correlating seasonal male moth catches to absolute infestation levels at harvest it was possible to indicate the density response of male moth catches in the pheromone trap (Sectar 1). Catch response was non-linear and the trap ceased to be indicative of higher infestation levels when accumulative catch exceeded about 100 moths/trap. Also, accumulative trap catches from the first few weeks of the season (before damage appeared) correlated well with eventual infestation levels indicating possible use of the pheromone trap as a predictive tool. Of the many factors influencing trap catch size the number of moth productive trees serviced by a trap (trap/tree ratio) was shown to be of critical importance.


1976 ◽  
Vol 108 (5) ◽  
pp. 449-460 ◽  
Author(s):  
Helmut Riedl ◽  
B. A. Croft ◽  
A. J. Howitt

AbstractThe relationship of pheromone trap catch to emergence and oviposition of the codling moth was defined for the two-generation climate of Michigan. Catch anticipated emergence and oviposition during spring flight when the trap displayed greatest efficiency, but lagged behind emergence and closely followed oviposition during the second generation. Trapping efficiency declined towards the end of the first generation and was generally lower during summer flight. Factors which possibly relate to this efficiency loss are discussed. First catch and the catch peaks in both generations were evaluated as reference points for the prediction of phenological events (particularly egg hatch) in both generations Of four forecasting methods, degree day and developmental unit summations, starting from first catch, for the preoviposition and incubation period were most reliable in predicting the beginning of spring brood egg hatch.


1976 ◽  
Vol 66 (2) ◽  
pp. 279-300 ◽  
Author(s):  
R. J. Marks

AbstractThe synthetic sex pheromone (dicastalure) of the red bollworm of cotton, Diparopsis castanea Hmps., in Central and Southern Africa, and an inhibitor of male sexual attraction (trans-9-dodecenyl acetate,=IIA), were used in an enclosed 0·2 ha cotton field-cage to reduce successful female matings. Over one month dicastalure at 21·0 and 42·3 g/ha produced average reductions in mating of 47·9% and 72·5% respectively and 37·9 g IIA/ha produced an overall reduction in mating of 71·5%, or 79·5% in released moth populations, over the same period. The proportion of virgin females present in disruption situations was significantly greater than in untreated populations and was density-independent for moth populations of up to 2 200/ha. The proportion of fertile eggs in disruption situations was correspondingly reduced to 30·2% from an average of 67·9% in control cycles. Reduction in sex pheromone trap catches is an unsatisfactory indicator of the extent to which males are prevented from inseminating females and considerably over-estimates the true degree of disruption. This is the first time that a naturally occurring inhibitor has been used successfully to disrupt mating in a field population of insects and it indicates the potential of the method for the control of high density pest populations in cotton. However, use of polyethylene dispensing mechanisms similar to those used in the field-cage disruption experiments would be unsuitable as a practical method of dispensing behaviour modifying chemicals and it is suggested that, for suitably controlled release of such chemicals, currently available microencapsulation technology offers the best prospects.


1998 ◽  
Vol 88 (5) ◽  
pp. 545-552 ◽  
Author(s):  
D. Scholz ◽  
C. Borgemeister ◽  
R. H. Markham ◽  
H. M. Poehling

AbstractIn an outdoor experimental set-up, the number of Prostephanus truncatus (Horn) flying from maize cobs was recorded over 38 observation weeks. Flight activity in the field was recorded for 50 weeks with three pheromone traps, each placed at c. 100–300 m from the first experimental set-up. Multiple regression analyses revealed that both flight initiation and flight activity were partly influenced by mean temperatures, but were not directly related. Flight initiation was mainly dependent on population density. An additional experiment showed that sex ratios among pheromone trap catches were not correlated with the number of beetles caught; sex ratios were female-biased throughout the year. Seasonal fluctuations in flight activity recorded with pheromone traps are mainly dependent on changes in the number and sizes of beetle populations in a given area, as well as on breeding site availability and suitability.


Sign in / Sign up

Export Citation Format

Share Document