Reference

Field and laboratory evaluation of the influence of copper-diquat on apple snails in Southern Florida

Field and laboratory evaluation of the influence of copper-diquat on apple snails in Southern Florida. Winger, Parley V.; Imlay, Marc J.; McMillan, Wayne E.; Martin, Thomas W.; Takekawa, Jean; Johnson, W. Waynon (Columbia Natl. Fish. Res. Lab., U. S. Fish and Wildl. Serv., Athens, GA 30602, USA). Environ. Toxicol. Chem., 3(3), 409-24 (English) 1984. CODEN: ETOCDK. ISSN: 0730-7268. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Section cross-reference(s): 5 The recent decline of apple snail (Pomacea paludosa) populations in canals surrounding Loxahatchee National Wildlife Refuge in Southern Florida coincided with the use Cu-diquat (I) [2764-72-9] for the control of the aquatic weed hydrilla (Hydrilla verticillata). Field and lab. studies were designed to assess the effects of Cu-diquat on apple snails, which are the primary food of the endangered snail kite Rostrhamus sociabilis (formerly known as the Everglade kite). Acute toxicities of Cutrine-Plus [66555-33-7] and Komeen [52769-67-2] (chelated formulations of Cu) to immature apple snails were 22 and 24 mg/L, resp. Diquat was toxic at 1800 mg/L and did not increase the toxicity of Cu when the chems. were used in combination. Evaluation of field samples indicated that Cu concns. were higher in detritus than in water, plants and mud, and that there was gradient of Cu concn. from the canal to the interior, the highest residues being in samples from the canal. Cu assocd. with detritus (up to 150 mg/g) had no effect on growth or survival of apple snails in field cage and tank studied. Also, field applications of Cu-diquat to hydrilla had no effect on survival of caged adult and immature snails. Cu from field applications was rapidly taken out of soln. by plants and org. material in the water and subsequently incorporated into the bottom detritus. Although the effects of repeated applications of Cu-diquat and high body burdens of Cu (accumulated during exposure to herbicidal treatment) on survival and reprodn. of apple snails are not known, the information available indicates that treatment of hydrilla with Cu-diquat was probably not responsible for the decline in the apple snail population. Application at recommended rates should pose no threat to these snails in the organically rich waters of Southern Florida.

Chemical defoliation of cucumber vines for simulation of once-over harvest in small-plot yield trials

Chemical defoliation of cucumber vines for simulation of once-over harvest in small-plot yield trials. Wehner, Todd C.; Monaco, Thomas J.; Bonanno, A. Richard (Dep. Hortic. Sci., North Carolina State Univ., Raleigh, NC 27695-7609, USA). HortScience, 19(5), 671-3 (English) 1984. CODEN: HJHSAR. ISSN: 0018-5345. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) Chem. defoliation of cucumber (Cucumis sativus) vines was evaluated as a method for rapid screening of breeding lines. Dinoseb [88-85-7], diquat [2764-72-9], ethephon [16672-87-0], glufosinate [51276-47-2], glyphosate [1071-83-6], and paraquat [4685-14-7] were used at 1 or 2 rates, on one pickling and 1 fresh-market cucumber cultivar (Calypso and Poinsett 76, resp.), to det. speed of vine defoliation and amt. of fruit damage. Paraquat, at 0.6 kg/ha, provided the most rapid defoliation (85% to 91% defoliaton 1 day after treatment), but caused some bleaching and chlorosis of the fruit. If the fruits were rolled 180° during evaluation, the damage was not noticeable. Chem. defoliation of vines for simulated once-over harvest provided a rapid, labor-saving method, requiring only 42% of the time to evaluate each plot compared to the conventional method. The chem. defoliation method is esp. useful for initial evaluation of populations and breeding lines for fruit yield and other horticultural characteristics.