Responses of Pests to Fumigation. VI.—Water Losses and the Mortality of<i>Calandra</i>Spp. at reduced Pressures

Bhambhani, H. J.

doi:10.1017/s0007485300046988

Cited by 10 publications

(3 citation statements)

References 7 publications

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“…Numerous studies have noted a reduction in weight due to moisture loss in vacuum-treated insects and that high humidities can reduce efÞcacy of vacuum treatments (El Nahal 1953, Bhambhani 1956, Chen et al 2006. Jay et al (1971) noted that mortality of stored product insects increased with decreasing relative humidity under low oxygen treatments at atmospheric pressures, and attributed this effect to dehydration.…”

Section: Discussionmentioning

confidence: 99%

Effect of Relative Humidity and Product Moisture on Response of Diapausing and Nondiapausing Indianmeal Moth (Lepidoptera: Pyralidae) Larvae to Low Pressure Treatments

Johnson

2010

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Low pressure treatment in flexible polyvinyl chloride containers is a potential alternative to chemical fumigants for California tree nuts. Laboratory studies investigated the effect of relative humidity and product moisture on weight loss and mortality of diapausing and nondiapausing larvae of the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), exposed to 50 mmHg. Diapausing larvae were far more tolerant than nondiapausing larvae to low pressure; exposure times nearly twice those of nondiapausing larvae were required to obtain comparable weight loss or mortality levels in diapausing larvae. Relative humidity was found to have a large effect on both weight loss (assumed to be due to moisture loss) and mortality of both nondiapausing and diapausing larvae. Mortality and weight loss increased as humidity levels decreased. By controlling the relative humidity of the treatment chamber, product moisture also strongly affected weight loss and mortality. The results suggest that for tree nuts, product moisture levels may affect the efficacy of low pressure treatments.

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Section: Discussionmentioning

confidence: 99%

Effect of Relative Humidity and Product Moisture on Response of Diapausing and Nondiapausing Indianmeal Moth (Lepidoptera: Pyralidae) Larvae to Low Pressure Treatments

Johnson

2010

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“…mercury) sorption appeared to be reduced. This change has been discussed in more detail by Bhambhani (1956a). Pradhan & Bhatia (1951) measured both sorption of hydrogen cyanide and recovery of this fumigant from insects.…”

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confidence: 92%

“…There are two main types of circumstance that seem to give rise to departures from this working rule. In the first place, a given concentration-time product is much more effective at low pressures than at atmospheric pressure (Salmond, 1953; El Nahal, 1953a), a discrepancy which cannot be accounted for by the mortality that arises at low pressures in the absence of fumigant (El Nahal, 19536;Bhambhani, 1956a). El Nahal (1953c) found that hydrogen cyanide is sorbed more strongly on wheat in sacks if the fumigation is done at low pressures than at atmospheric pressure, even when full allowance is made for the greater concentration-time products obtained in the sustained vacuum fumigations.…”

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confidence: 99%

Responses of Pests to Fumigation.VII.—The Relation between Fumigation Techniques, Mortality, and the Amount of Hydrogen Cyanide sorbed by Calandra spp.

Bhambhani¹,

Blackith²

1958

Bull. Entomol. Res.

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The relation between fumigation techniques, mortality and sorption of fumigant was investigated by two factorial experiments in which adults of Calandra granaria (L.) and C. oryzae (L.) were exposed to hydrogen cyanide at concentrations of 12, 26 or 44 mg. per litre and pressures of 2, 27, 52 and 76 cm. mercury for 30, 60 or 90 min., or at given concentration-time products (36, 72 or 108 mg. hr. per litre), in each of which the time component was 1, 4 or 12 hr., and pressures of 2, 37 and 76 cm. mercury. The methods of fumigation and estimation of sorption and mortality were those used in earlier investigations and the results are shown in a series of graphs.For both species, sorption of hydrogen cyanide increased as the total pressure was reduced, about three times as much being sorbed, in the first experiment, at a pressure of 2 cm. as at atmospheric pressure, the increase in sorptive capacity being greater in the case of C. oryzae than in that of C. granaria. In the second experiment, sorption by both species, for a given concentration-time product, was greater at a high concentration applied for a short period (1 hr.) than at a lower concentration applied for a long period (12 hr.); in the former conditions, C. granaria consistently sorbed more fumigant than did C. oryzae, in the latter, the reverse was the case, and in intermediate conditions (4 hr. exposure), the amounts sorbed by the two species did not differ materially. This result was inconsistent with that of the first experiment, in which C. oryzae sorbed more than did C. granaria during short exposures (30.90 min.).These effects on sorptive capacity of differing conditions of fumigation could account for most of the reported departures from the rule that the biological effects of fumigation can be described by the product of the mean concentration of fumigant applied and the period of exposure. Comparison between mortality and sorption at pressures of 27–76 cm. in the first experiment showed, however, that while these were broadly associated, the increased mortality at higher concentrations was greater than would be expected from the associated increase in sorption, and this discrepancy was significantly larger for C. oryzae than for C. granaria.

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The response of Tenebroides mauritanicus (L.) and Tenebrio molitor L. to methyl bromide at reduced pressures

Monro¹

1959

J Sci Food Agric

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The response of larvae and adults of Tenebroides mauritanicus (L.) to methyl bromide at reduced pressures is complex. Four zones of differing susceptibility were found : (1) at 15–30 mm. Hg pressure high mortalities were due more to desiccation than the action of the fumigant; (2) at 30–50 mm. low mortalities coincided with loss of visible activity; (3) at 50–175 mm. increased activity and high mortalities occurred; (4) from 175 mm. to atmospheric pressure activity was normal and mortalities declined. In zones (2) to (4) the responses were independent of humidity. Larvae of Tenebrio molitor L. gave responses similar to those in zones (2), (3) and (4) but at different pressure ranges.

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Responses of Pests to Fumigation. VI.—Water Losses and the Mortality ofCalandraSpp. at reduced Pressures

Cited by 10 publications

References 7 publications

Effect of Relative Humidity and Product Moisture on Response of Diapausing and Nondiapausing Indianmeal Moth (Lepidoptera: Pyralidae) Larvae to Low Pressure Treatments

Effect of Relative Humidity and Product Moisture on Response of Diapausing and Nondiapausing Indianmeal Moth (Lepidoptera: Pyralidae) Larvae to Low Pressure Treatments

Responses of Pests to Fumigation.VII.—The Relation between Fumigation Techniques, Mortality, and the Amount of Hydrogen Cyanide sorbed by Calandra spp.

The response of Tenebroides mauritanicus (L.) and Tenebrio molitor L. to methyl bromide at reduced pressures

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