A laboratory study of the effects of some soil-applied organophosphorus pesticides on Carabidae (Coleoptera)

Abstract

Time/mortality studies with Carabidae exposed to thionazin, phorate, disulfoton and menazon in an acid sandy loam soil were done in controlled laboratory conditions. Carabids were killed by soil treated with thionazin within dosage rates normally required for satisfactory control of nematode or insect pests of crops, i.e., 2·24–8·96 kg/ha, but menazon was virtually non-toxic. Soil moisture increased the speed of kill of Carabidae in thionazin-treated soil presumably by affecting processes of adsorption and desorption of the pesticide to soil colloids and by influencing burrowing behaviour. The speed of kill increased with a rise in temperature, mortalities occurring 2·2 × faster at 10°C, 8·1 × faster at 15°C and 11·8 × faster at 22°C than at 7°C, but was decreased by illumination which decreased the activity of the nocturnal Carabids. The addition of calcium carbonate to increase soil pH did not alter immediate mortality by thionazin but persistence was decreased. Speed of kill was negatively correlated with adult size of Carabid species that behaved similarly, small species such as Bembidion lampros (Hbst.) (mean weight 2·1–2·2 mg) dying 12–13 × faster than female adults of Pterostichus vulgaris (L.) (mean weight 195 mg). Species which burrowed in soil were more susceptible than those which did not, as were newly moulted or starved adults. At 15°C and in wet conditions the “ half-life ” of thionazin based on speed of kill in a soil of pH 6·1–6·7 was 1–2 weeks but when determined by gas-liquid chromatography was 3–4 weeks at 22°C. Leaching could account for the loss of up to 12% of thionazin from the top 9 cm of soil.

Field investigations on the effects of an organophosphorus pesticide, thionazin, on predacious Carabidae (Coleoptera)

“…6-7) and showed that thionazin disappeared most rapidly from the surface half-inch (1-3 cm) layer. Leaching rather than chemical or biological degradation appeared to be most responsible for this (Critchley, 1972). Results in the field differed from those in the laboratory (Fig.…”

“…Laboratory-treated soil (Critchley, 1972) was placed in modified plastic pill boxes. These had their " tops" and " bottoms " replaced by either fine mesh linen gauze (Experiment I) or nylon-terylene gauze (Experiment II) and were built up to form columns 3J-in.…”

“…The species affected most by the treatments appeared to be the smaller ones of mean weight 1-5-5-0 mg, such as B. lampros, B. quadrimaculatum and T. quadristriatus, whereas the larger species such as P. vulgaris, P. madidus and C. fuscipes were least affected. These differences must not only have been due to differences in their size as indicated by laboratory tests (Critchley, 1972) but also to the later appearance of the larger species (Fig. 1-2) when some of the pesticide would have disappeared (Fig.…”

“…Comparatively little attention has been paid to the effects of organophosphorus pesticides on Carabidae (Dinther, 1963;Griffiths et al, 1967;Mowat & Coaker, 1967;Voronova, 1968;Edwards et al, 1970). Recent laboratory studies (Critchley, 1972) have shown that Carabidae are susceptible to thionazin at 2-8 lb active ingredient (a.i. )/acre (2-24-8-96 kg/ha) in a light sandy loam soil.…”

Are carabid beetles suitable biotic indicators of insecticide impact in potato fields?

“…chalcites, had intermediate rates of mortality. Critchley (1972a) reported that small species, such as Bembidion lampros (mean weight 2.1 mg), died 12 or 13 times faster than Pterostichus vulgaris (mean weight 195 mg) under laboratory conditions. Body size (see Table 2) affects susceptibility to insecticides (Critchley, 1972a, b), but this possibility was not tested here because of the limited number of species tested.…”