A SEQUENTIAL DECISION PLAN FOR MANAGEMENT OF THE ALFALFA BLOTCH LEAFMINER, AGROMYZA FRONTELLA (DIPTERA: AGROMYZIDAE)

1983 ◽  
Vol 115 (11) ◽  
pp. 1513-1518 ◽  
Author(s):  
D. G. Harcourt

AbstractA sequential decision plan, based on the negative binomial distribution and providing for two infestation classes, has been derived for use in management of the alfalfa blotch leafminer, Agromyza frontella (Rond.), in southern Ontario. It utilizes counts of the eggs in leaflets of alfalfa, and in economic situations will provide growers with sufficient lead time to consider alternative action strategies. An appraisal of the plan by field scouts showed that it rated the infestation status of the leafminer correctly in 48 of 51 cases. Sampling time averaged 25 min per scout per field.

1976 ◽  
Vol 108 (5) ◽  
pp. 551-555 ◽  
Author(s):  
D. G. Harcourt ◽  
J. C. Guppy

AbstractA sequential decision plan, based on the Poisson distribution and providing for two infestation classes, was drawn up as an aid to management of the alfalfa weevil, Hypera postica (Gyll.), on first-growth alfalfa in Ontario. It is based on counts of the oviposition punctures in three-stem bouquets of alfalfa, and, in economic situations, will provide the grower with sufficient lead time to consider alternative action strategies. An appraisal of the plan under field conditions showed that it rated the infestation status of the weevil correctly in 56 of 60 cases. Sampling time averaged 35 man-min.


1980 ◽  
Vol 112 (4) ◽  
pp. 375-385 ◽  
Author(s):  
D. G. Harcourt ◽  
M. R. Binns

AbstractDuring 1977, a detailed study was undertaken to develop efficient sampling procedures for estimating egg and larval populations of the alfalfa blotch leafminer, Agromyza frontella (Rond.), in Vernal alfalfa. Distributions of the stages within and between stems were contagious and stem totals tended to follow negative binomial distributions. Within stems, the density of eggs and larval mines increased exponentially from base to tip. Taking these patterns and the costs of sampling into account, and using the relevant components of variance, four leaves taken systematically from a single stem is proposed as the appropriate sample unit for both eggs and mines. On this basis, 200 stems per field will give adequate precision (less than 10% of the mean with confidence probability 90%) for population estimates. However, the propensity of the leafminer to prefer the middle leaflet to the basal leaflets in the approximate ratio 3:4:3 suggests that sampling costs may be further reduced by restricting counts to the middle leaflet and raising them by a factor of 2.5.


1988 ◽  
Vol 28 (2) ◽  
pp. 279 ◽  
Author(s):  
PG Allsopp ◽  
S Iwao ◽  
LR Taylor

Counts of adults of mixed populations of Nysius vinitor Bergroth and N. clevelandensis Evans on preflowering and postflowering sunflowers did not conform to the Poisson distribution because of overdispersion. Preflowering samples did not conform to the negative binomial model, but postflowering samples did with a common k of 3.78. Both sets of samples fitted significantly (P<0.01) Iwao's patchiness regression and Taylor's power law, but with significantly (P<0.01) different intercepts and slopes, respectively. Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines are developed for both stages of crop development using Taylor's power law. Sequential decision plans based on Iwao's regression are developed for use in the management of Nysius spp. on preflowering and postflowering sunflowers.


1988 ◽  
Vol 14 (3) ◽  
pp. 947-956 ◽  
Author(s):  
Yves Carri�re ◽  
Jocelyn G. Millar ◽  
Jeremy N. McNeil ◽  
David Miller ◽  
E. W. Underbill

2001 ◽  
Vol 133 (5) ◽  
pp. 717-719 ◽  
Author(s):  
Arild Andersen ◽  
Jeremy N. McNeil

Male size is an important parameter in mate choice for many species and has been associated with such female life-history parameters as increased fecundity or fertility and larger progeny (Phelan and Baker 1986; Savalli and Fox 1998, 1999; Brown 1999). In the alfalfa blotch leafminer, Agromyza frontella (Rondani), intraspecific larval competition may significantly influence the size of both males and females (Quiring and McNeil 1984a). The influence of female size on female reproductive success has been studied (Quiring and McNeil 1984b, 1984c), but to date, no attention has been given to the possible effects of male size. The objectives of this study were to determine if differences in male size, the result of intraspecific larval competition, affected male longevity and reproductive success, as well as various parameters of female reproduction.


1981 ◽  
Vol 113 (7) ◽  
pp. 593-600 ◽  
Author(s):  
J. C. Guppy

AbstractThe alfalfa blotch leafminer, Agromyza frontella (Rondani), typically develops through three complete generations a year. It overwinters as a partially developed pupa that completes its development in mid-May. Three distinct adult flight periods occur: mid-May to mid-June, late June to late July, and early to late August. Eggs are deposited singly in alfalfa leaflets beneath the lower epidermis and on hatching, the larvae move toward the upper leaflet surface where they feed on the mesophyll and develop through three instars to form blotch mines, each representing about 27% of the leaflet area. The mature larvae emerge from the mines and drop to the soil to form light brown puparia, mainly in the top 2.5 cm of soil.Duration of each stage decreased with rise in temperature up to 25° but none of the stages survived 30°C. Developmental rates plotted against temperature gave highly correlated linear relationships for all stages. The theoretical threshold for the egg, larva, and pupa was 7°, 3°, and 4°C, respectively; thermal requirements for these stages were 55, 123, and 333°D, respectively.Survival of the larvae was higher in leaflets with solitary mines than in those with multiple mines; only 25% of the leaflets with two mines gave rise to two mature larvae. Three larvae seldom survived in a single leaflet.


1991 ◽  
Vol 69 (7) ◽  
pp. 1100-1106 ◽  
Author(s):  
David Miller ◽  
François Bilodeau ◽  
Robert H. Burnell

Two related stereoselective syntheses of 3,7-dimethylnonadecane, a sex pheromone of the alfalfa leafminer, are described to show that pulegone can serve as a useful starting material for the preparation of chiral aliphatic isoprenoid compounds. The schemes are designed to place the stereogenic center of pulegone at C.3 in one synthesis and at C.7 in the other so that the optical properties of the products can be compared with one another and with the values calculated using Brewster's rules. Key words: chiral hydrocarbons, stereoselective synthesis, pheromone, Agromyza frontella.


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