BIOLOGY OF AGAPETA ZOEGANA (LEPIDOPTERA: COCHYLIDAE), PROPAGATED FOR THE BIOLOGICAL CONTROL OF KNAPWEEDS (ASTERACEAE)

2000 ◽  
Vol 132 (2) ◽  
pp. 223-230 ◽  
Author(s):  
George W. Powell ◽  
Brian M. Wikeem ◽  
Allen Sturko
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Adult Emergence ◽  
Larval Survival ◽  
Control Agent ◽  
Spotted Knapweed ◽  
Degree Days ◽  
Centaurea Diffusa ◽  
Calendar Date ◽  
Accumulated Degree Days

AbstractWe examined the influence of temperature and release density on the root-boring moth, Agapeta zoegana L., a biological control agent of diffuse knapweed, Centaurea diffusa Lam., and spotted knapweed, Centaurea maculosa Lam. Moths were released at six densities (1, 2, 4, 8, 16, and 32 adult male–female pairs) in each of 2 years (1992 and 1993 cohorts) into outdoor, caged plots containing spotted knapweed. Air temperature, larval establishment and mass, and adult emergence, mass, and body dimensions were measured. Larval production increased linearly with adult release density in both cohorts. Larval survival ranged from 0 to 100% and was not correlated with release density or accumulated degree-days in either year. Date of first emergence occurred earlier as both release density and larvae per plant increased, but only for the 1992 cohort. Declining resources or increased contact among the larvae may induce early pupation. Peak emergence rate increased with release density in both cohorts. First emergence was related more closely to calendar date than accumulated degree-days. In contrast, peak emergence rates were more consistent with degree-day accumulations between cohorts than calendar date. Adult production increased with parental release density in both cohorts. Females were heavier, wider, and longer than males. Optimal A. zoegana production will be achieved with releases of greater than 1.6 male–female adult pairs per spotted knapweed plant.

BIOLOGY OF CYPHOCLEONVS ACHATES (COLEOPTERA: CURCULIONIDAE), PROPAGATED FOR THE BIOLOGICAL CONTROL OF KNAPWEEDS (ASTERACEAE)

1999 ◽  
Vol 131 (2) ◽  
pp. 243-250 ◽  
Author(s):  
Brian M. Wikeem ◽  
George W. Powell ◽  
Allen Sturko
Keyword(s):  
Biological Control ◽  
Adult Emergence ◽  
Larval Survival ◽  
Specific Information ◽  
Spotted Knapweed ◽  
Degree Days ◽  
Centaurea Diffusa ◽  
Larval Production ◽  
Competition For Food ◽  
Diffuse Knapweed

AbstractCyphocleonus achates (Fahraeus) is a weevil used for the biological control of diffuse knapweed, Centaurea diffusa Monnet Del La Marck, and spotted knapweed, Centaurea maculosa Monnet Del La Marck, in North America. This research provided specific information on the biology of this insect in British Columbia. Adult weevils were released at six densities (1, 2, 4, 8, 16, and 32 male–female pairs) in each of 2 years into plots containing spotted knapweed. Larvae per plant, larval mass, larval survival, adult emergence, and air temperature were measured. Larval production increased with the release density of weevils in both the 1992 cohort and the 1993 cohort. Larval mass did not differ between years. Larval mass also did not vary with the release density of adults or the number of larvae per root. Larval survival of the 1993 cohort ranged from 17 to 48%, whereas that of the 1994 cohort ranged from 0 to 91%. Adult emergence began after the accumulation of 726–1144 degree-days. For both cohorts the date of first emergence occurred earlier, as the average number of larvae per plant increased for both cohorts. Increasing competition for food or space in the roots can induce early emergence. Sex ratios did not vary with date of emergence or release density of adult weevils. Adult emergence increased with the release density in the 1992 cohort, suggesting the average larval densities did not exceed the carrying capacity of the roots. The peak emergence rate increased with the release density in the 1992 cohort, but not in the 1993 cohort because of lower larval survival.

Biological Control of Diffuse Knapweed (Centaurea diffusa) and Spotted Knapweed (C. maculosa)

Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Donald M. Maddox
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Reproductive Potential ◽  
Control Agent ◽  
Flower Head ◽  
Spotted Knapweed ◽  
Centaurea Diffusa ◽  
Weedy Species ◽  
Diffuse Knapweed ◽  
Number Of Seeds

Diffuse knapweed (Centaurea diffusa Lam.) and spotted knapweed (C. maculosa Lam.) presently infest approximately 1.5 million ha of pasture and rangeland in Washington, Montana, Idaho, Oregon, and California. The serious losses caused on lands where returns from herbicidal control are marginal or less prompted the testing and introduction of two strains of a seed-head fly (Urophora affinis Frlfld.) as a biological-control agent in these states. Over 27 000 flies were released in about equal numbers on both weeds during the years 1974 to 1977 and in 1979 and 1980. The fly became established in all states where it was released. The adult was found to disperse over 76 m from release point from 1974 to 1976, and to reduce the number of seeds per flower head in sampled heads by 80% in northern Washington and over 64% at the Heppner, Oregon site. A newly released moth (Metzneria paucipunctella Zell.) and a root-boring beetle (Spbenoptera jugoslavica Obenb.) are expected to cause additional pressure on these plants. The reproductive potential of the knapweeds is such that more natural enemies will be needed to provide enough stress to reduce these weedy species to an acceptable level.

THERMAL REQUIREMENTS FOR DEVELOPMENT OF COLEOMEGILLA MACULATA (COLEOPTERA: COCCINELLIDAE) AND ITS PARASITE PERILITUS COCCINELLAE (HYMENOPTERA: BRACONIDAE)

1978 ◽  
Vol 110 (4) ◽  
pp. 407-412 ◽  
Author(s):  
John J. Obrycki ◽  
Maurice J. Tauber
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Adult Emergence ◽  
Control Agent ◽  
Coleomegilla Maculata ◽  
Optimum Temperature ◽  
Degree Days ◽  
Temperature Range ◽  
Thermal Requirements ◽  
Dietary Requirements

AbstractThe optimum temperature range for development and survival of the predacious coccinellid Coleomegilla maculata and its parasite Perilitus coccinellae is 24° to 26.7°C. Theoretical thresholds for development (t) of the pre-imaginal stages of C. maculata range from 9° to 13°C. Total development (from oviposition to adult emergence) of the beetle requires an accumulation of 236 heat degree days (K) above 11.3°C (t), whereas the development of P. coccinellae requires 395 heat degree days (K) above 9.8°C (t). To predict the seasonal interaction between C. maculata and P. coccinellae, and to manage C. maculata efficiently as a biological control agent, it is vital to know the thermal and dietary requirements of the two species.

scholarly journals Field demonstration of a semiochemical treatment that enhances Diorhabda carinulata biological control of Tamarix spp.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexander M. Gaffke ◽  
Sharlene E. Sing ◽  
Tom L. Dudley ◽  
Daniel W. Bean ◽  
Justin A. Russak ◽  
...  
Keyword(s):  
Biological Control ◽  
Aggregation Pheromone ◽  
Biological Control Agent ◽  
Adult Emergence ◽  
Classical Biological Control ◽  
The United States ◽  
Control Agent ◽  
Weed Biological Control ◽  
Single Well ◽  
Tamarix Spp

Abstract The northern tamarisk beetle Diorhabda carinulata (Desbrochers) was approved for release in the United States for classical biological control of a complex of invasive saltcedar species and their hybrids (Tamarix spp.). An aggregation pheromone used by D. carinulata to locate conspecifics is fundamental to colonization and reproductive success. A specialized matrix formulated for controlled release of this aggregation pheromone was developed as a lure to manipulate adult densities in the field. One application of the lure at onset of adult emergence for each generation provided long term attraction and retention of D. carinulata adults on treated Tamarix spp. plants. Treated plants exhibited greater levels of defoliation, dieback and canopy reduction. Application of a single, well-timed aggregation pheromone treatment per generation increased the efficacy of this classical weed biological control agent.

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