The Persistence and Fate of DDT on Foliage. II.—Comparative Rates of Loss of DDT Deposits from Glass Plates and Growing Leaves

Ward, J.; Burt, P. E.

doi:10.1017/s000748530003710x

Cited by 7 publications

(2 citation statements)

References 13 publications

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“…A small proportion of the leaves that had been very close to the spraying lance had received applications so excessive that the insecticide had run off the leaves; such leaves were discarded as they were very much in the minority. No attention was paid to which plants were sampled as it has been shown that differences in toxicity between various leaf surfaces can be very small provided the deposits are of the same concentration and without oil carriers (Ward & Burt, 1955).…”

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confidence: 99%

An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)

Baldry

1963

Bull. Entomol. Res.

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The persistence of DDT deposits, derived from dilutions of an emulsion concentrate, Arkotine D.25, on the leaves of riverine vegetation in the Northern Guinea Savannah vegetation zone of Nigeria was studied in the laboratory by a bioassay method using teneral females of Glossina palpalis (R.-D.) as test insects. Irrespective of whether sprayed in the dry or wet season, deposits derived from sprays containing 5.0 per cent. DDT produced by the Warley knapsack sprayer were still reasonably toxic one year after spraying. Deposits derived from sprays having a concentration of DDT varying from 1·25 to 5·0 per cent. DDT were equally toxic when young, but those from the lower concentrations were weathered much more rapidly than those from the 5·0 per cent, sprays. Young deposits produced by Warley and Motoblo sprayers were equally toxic, but deposits from the Motoblo deteriorated more rapidly than those of the Warley.The toxicity of the DDT deposits on leaves varied regularly with the seasons. The various climatic factors that it is thought influenced the variations in toxicity are discussed. Accumulations of wind-blown dust on the leaves during the late dry season and low evaporation rates at the height of the rains appear to be responsible for reduced toxicity at those times; in the early wet season, the occasional violent storm probably washes off the leaves the dust accumulated during the dry season and makes the insecticidal deposits once more available. Heavy rainfall is important in removing the insecticidal deposits from the vegetation, and leaf decay and refoliation are important in reducing the availability of the deposits. The implications of these variations in toxicity and factors that reduce the availability of the deposits are discussed in relation to the eradication of riverine tsetse.Great differences in the rates of foliage decay and refoliation occur between different riverine plants, and it is suggested that a thorough study of this feature in riverine plants and of resting sites favoured by tsetse flies might reveal information that would enable tsetse to be eradicated by selective spraying of certain plant species only.

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mentioning

confidence: 99%

An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)

Baldry

1963

Bull. Entomol. Res.

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“…Where the ovicidal effect of a material was to be tested, shoots bearing eggs were selected, or female mites were placed on the shoots and left there until sufficient eggs had been laid. The spray was applied as a fine mist to the entire upper surface of the single leaf by the method of Burt & Ward (1956) for depositing an even film on attached leaves. An ' Air-brush ' equipment delivered 2 ml.…”

Section: Experimental Methodsmentioning

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New acaricides for control of the red spider mite, Oligonychus coffeae (Nietner), on tea

Mukerjea

1962

Bull. Entomol. Res.

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Laboratory and field tests were made to investigate the acaricidal properties of Tedion (2,4,5,4′-tetrachlorodiphenyl sulphone) and Kelthane (l,l-di(p-chlorophenyl)-2,2,2-trichloroethanol) and to compare them with Akar 338 (ethyl 4,4′-dichlorobenzilate), malathion (in field tests only), lime sulphur and the organophosphorus compounds Rogor (O,O-dimethyl S-methylcarbamoyhmethyl phosphorodithioate) and Ekatin (O,O-dimethyl S-2-(ethylthio)ethyl phosphorodithioate) against the red spider mite, Oligonychus coffeae (Nietn.), on tea in Assam during 1958–60. The materials were available at the following concentrations of active ingredient: Tedion emulsifiable concentrate (8 per cent, w/v), Kelthane wettable powder (18·5 per cent, w/w), Akar 338 emulsifiable concentrate (25 per cent, w/v), malathion emulsifiable concentrate (56 per cent, w/v), lime sulphur solution (24–26 per cent, polysulphide), Rogor emulsifiable concentrate, (40 per cent, w/v) and Ekatin emulsifiable concentrate (20 per cent. w/v). Tedion was also available as a wettable powder (8 per cent, w/w) and Kelthane as an emulsifiable concentrate (18·5 per cent. w/v). In the laboratory, the first three and Rogor were usually diluted to 1 part in 500 with water, Ekatin to one part in 1,000 and lime sulphur to 1 in 40, but Tedion was also tested in some experiments at 1:750, 1:1,000 and 1:1,500. Using a single-leaf technique in the laboratory, 2 ml. of spray were applied to each leaf. Sprayed directly on to the eggs, Tedion and Kelthane gave equally good kills (97·7 and 90·7 per cent., respectively) and were more effective than Akar 338 (47·9%) or Ekatin (27%). There was some evidence that Tedion may be more effective as a deposit on which eggs are subsequently laid than as a direct spray. It also has a toxic effect on the eggs developing in the ovary, maximum effect (0·5 per cent, viability) being observed in eggs laid on unsprayed leaves on the second day after spraying of the female. The effect declined slowly towards the fifth day and by the ninth day had practically been lost. Rogor was not tested against the eggs. At the concentration effective against eggs, Tedion had only a limited effect (38·7 per cent, mortality) on nymphs and adults 24 hr. after application. However, in two laboratory trials carried out on potted plants to compare the toxicities of Tedion, Akar 338 and lime sulphur under these conditions and to ascertain the persistence of their effects against nymphs and adults, whereas Akar 338 and lime sulphur were significantly more effective than Tedion after 24 hr. at the concentrations used, after one week the effect of the two former showed little change, whilst that of Tedion had increased greatly, and after two weeks was significantly greater than that of Akar 338 in both trials and in one of them after four weeks. The effect of lime sulphur at four weeks was not significantly different from that of Tedion and was superior to that of Akar 338 in one trial. Kelthane, Akar 338, Eogor and Ekatin, and also lime sulphur, gave 100 per cent, kill of nymphs and adults 24 hr. after application by the single-leaf technique. Kelthane, Rogor and Ekatin were not tested for persistence of effect. In the field, all sprays were applied at 100 gal. per acre. The same dilutions of Tedion, Kelthane, Akar 338 and lime sulphur as were used in the laboratory were applied, giving rates of 2·6, 6, 8, and 100 oz., respectively, of active ingredient per acre. Malathion was diluted to 1 part in 500, giving 18 oz. active ingredient per acre, and Eogor and Ekatin to 1 part in 1,000, giving 6·4 and 3·2 oz. per acre, respectively. Counts of numbers of mites on leaf samples taken 3, 7 and 15 days and one month after application in two trials in 1959 and one in 1960 indicated that, at the concentrations used, Tedion, although at almost every count it had reduced the mite population by over 90 per cent., as compared with the control, was not consistently significantly superior to Akar 338, Kelthane and Rogor. There was some indication that Ekatin and malathion might be less effective than Akar 338, Kelthane and Eogor. Lime sulphur was effective for a period up to 7–15 days.

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Movement of DDT and its derivatives into the atmosphere

Spencer¹

1975

Residue Reviews

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The Persistence and Fate of DDT on Foliage. II.—Comparative Rates of Loss of DDT Deposits from Glass Plates and Growing Leaves

Cited by 7 publications

References 13 publications

An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)

An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)

New acaricides for control of the red spider mite, Oligonychus coffeae (Nietner), on tea

Movement of DDT and its derivatives into the atmosphere

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