|
<br />, .
<br />
<br />277
<br />
<br />Effects of B/i on invenebrales
<br />
<br /> 100
<br /> 90
<br /> 60 CA 2nd & 3rd Inslar
<br />.~ III 4th Instar
<br />70
<br />~ 60
<br />0
<br />:::E 50
<br />E 40
<br />Q)
<br />0
<br />Q; 30
<br />a.
<br /> 20
<br /> 10
<br /> 0
<br />
<br />
<br />Control 0.0001 0.0005 0.001 0.01
<br />
<br />Concentration (ppm)
<br />
<br />Fig. 9. Relation of age (instar) on the toxicity of Vectobac-GI!> at
<br />four concentrations to Chironomus riparius (water-only exposure,
<br />N = 3, 10 larvae per replicate).
<br />
<br />food source did not reduce the susceptibility of chironomid
<br />larvae to Yectobac-G. These results also do not correspond
<br />with the findings of other studies with mosquito species
<br />[19,28). One study by Ignoffo et al. [65] reported the pres-
<br />ence of food increased the toxic effect of Bti to Aedes ae-
<br />gypti. They stated that food stimulated feeding, thereby
<br />increasing the probability that larvae ingested Bti.
<br />Our results indicate that the amount of organic matter in
<br />sediment does not affect the efficacy of Yectobac-G to chi-
<br />ronomid larvae. These results do not correspond with those
<br />in the literature for some mosquito species [24,67-69], al-
<br />though these studies were also evaluating suspended solids.
<br />
<br />CONCLUSION
<br />
<br />On the basis of the field and laboratory studies, Yectobac-
<br />G controls mosquito larvae without reducing nontarget chi-
<br />ronomid larvae when applied to wetlands of the type (types
<br />4 and 5) used in the enclosure tests. Where Yectobac-G is to
<br />be applied for mosquito control, it is recommended that the
<br />areas be classified as to the factors that influence the efficacy
<br />of Bti (water temperature, water depth, water clarity, cov-
<br />erage of submersed and emergent vegetation, and age of in-
<br />vertebrates). However, further testing is necessary to.better
<br />understand the mitigating effects of environmental factors
<br />on the toxicity of Bli to invertebrates under field conditions
<br />across a range of wetland types.
<br />
<br />Acknowtedgemenl- The authors are grateful to personnel at the Na-
<br />tional Fisheries Contaminant Research Center and the Minnesota
<br />Yalley National Wildlife Refuge for use of facilities and other sup-
<br />pon. We thank B. Wagner and T. LaPoint for statistical assistance,
<br />C. Ingersoll and B. Poulton for critical review of the manuscript,
<br />and T.J. Miller for initiating the project. This work was funded by
<br />the U.S. Fish and Wildlife Service, Ecological Services, Division of
<br />Environmental Contaminants, Twin Cities, Minnesota. This is a con-
<br />tribution from the Missouri Cooperative Fish and Wildlife Research
<br />Unit (U.S. Fish and Wildlife Service; Missouri Department of Con-
<br />servation; The School of Natural Resources, University of Missouri;
<br />and Wildlife Management InstitUle cooperating).
<br />
<br />REfERENCES
<br />
<br />I. Goldberg, L.J. and J. Margalit. 1977. A bacterial spore dem-
<br />onstrating rapid larvicidal activity against Anopheles sergen/ii,
<br />Vrano/aenia unguicuta/a, Culex univi/allus, Aedes aegyp/i and
<br />Culex pipiens. Mosq. News 37:355-358.
<br />2. Van Essen, F.W. and S.C. Hembree. 1980. Laboratory bioas-
<br />say of Bacillus /huringiensis israelensis against all instars of Ae-
<br />des aegyp/i and Aedes /aeniarhynchus larvae. Mosq. News
<br />40:424-431.
<br />3. Dame, D.A., K.E. Savage, M.V. Meisch and S.L. OIdacre. 1981.
<br />Assessment of industrial formulations of Bacillus /huringiensis
<br />var. israetensis. Mosq. News. 41:540-546.
<br />4. Krieg, A. and G.A. Langenbruch. 1981. Susceptibility of anhro-
<br />pod species to Bacillus thuringiensis. In H.D. Burges, ed., Mi-
<br />crobial Con/rol of Pests and Plan/ Diseases /970-/980.
<br />Academic, New York, NY, pp. 837-896.
<br />5. Purcell, B.H. 1981. Effects of Bacillus /huringiensis var. israe-
<br />lensis on Aedes (aeniarhynchus and some non-target organisms
<br />in the salt marsh. Mosq. News 41:476-484.
<br />6. Lacey, L.A. and S. Singer. 1982. Larvicidal activity of new iso-
<br />lates of Bacillus sphaericus and Bacillus thuringiensis (H-14)
<br />against anopheline and culicine mosquitoes. Mosq. News
<br />42:537-543.
<br />7. Eldridge, B.F., R.K. Washino and D. Henneberger. 1985. Con-
<br />trol of snow pool mosquitoes with Bacillus /huringiensis sero.
<br />type H-14 in mountain environments in California and Oregon.
<br />J. Am. Mosq. Control Assoc. 1:69-75.
<br />8. Mulla, M.S., H.A. Darwazeb, L. EcIe, B. Kennedy and H.T.
<br />Dulmage. 1985. Efficacy and field evaluation of Bacillus thu-
<br />ringiensis (H-14) and B. sphoericus against floodwater mosqui-
<br />toes in California. J. Am. Mosq. Con/rol Assoc. 1:310-315.
<br />9. Majori, G., A. Ali and G. SabatinelIi. 1987. Laboratory and
<br />field efficacy of Bacillus thuringiensis var. israelensis and Ba-
<br />cillus sphaericus against Anopheles gambiae S.L. and Cutex
<br />quinquefascia/us in Ouagadougou, Burkina Faso. Mosq. News
<br />3:20-25.
<br />10. Mullen, G.R. and N.C. Hinkle. 1988. Method for determining
<br />settling rates of Bacillus thuringiensis serotype H.14 formula-
<br />tions.1. Am. Mosq. Control Assoc. 4:132-137.
<br />II. Colbo, M.H. and A.H. Undeen. 1980. Effect of Bacillus thu-
<br />ringiensis var. israelensis on non-target insects in stream trials
<br />for control of Simuliidae. Mosq. News 40:368-371.
<br />12. Molloy, D. and H. Jamnback_ 1981. Field evaluation of Bacil-
<br />lus thuringiensis var. israelensis as a blackfly biocontrol agent
<br />and its effect on nontarget stream insects. J. Econ. Entomot.
<br />74:314-318.
<br />13. Molloy, D., R. Gaugler and H. Jamnback. 1981. Factors influ-
<br />encing efficacy of Bacillus thuringiensis var. israetensis as a bio-
<br />logical control agent of blackfly larvae. J. fron. Entomot.
<br />74:61-64.
<br />14. Pistnmg, L.A. and J.F. Burger. 1984. Effect of Bacillus thurin-
<br />giensis var. israelensis on a genetically-defined population of
<br />black flies (Diptera: Simuliidae) and associated insects in a mon-
<br />tane New Hampshire stream. Can. En/omol. 116:975-981.
<br />15. Gibbs, K.E., F.C. Brautigam, C.S. Stubbs and L.M. Zibilske.
<br />1966. Experimental applications of Bacillus /huringiensis israe-
<br />lensis for larval black fly control: Persistence and downstream
<br />carry, efficacy, impact on nontarget invertebrates and fish feed-
<br />ing. Technical Bulletin 123. Maine Agricultural Station, Orono,
<br />ME.
<br />16. All, A. 1981. Bacillus /huringiensis serovar. israelensis (ABG-
<br />6108) against chironomids and some nontarget aquatic invene-
<br />brates. J. Invert. Pathol. 38:264-272.
<br />17. Garcia, R., B. Des Rochers and W. Tozer. 1980. Bacillus thu-
<br />ringiensis var. israelensis against mosquito larvae and other or-
<br />ganisms. In Annual Repon of Mosquito Control ReSearch.
<br />University of California, Fresno, CA, pp. 54-57.
<br />18. Miura, T., R.M. Takahashi and F.S. Mulligan 111.1980. Effects
<br />of the bacterial mosquito lan'icide, Bacillus /huringiensis sero-
<br />type H-14 on selected aquatic organisms. Mosq. News 40:619-
<br />622.
<br />
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