Technical notes. Parasites of Sorghum midge, Contarinia sorghicola (Coq.), in Queensland

During the seven years' study period the highest percentage of parasites in any population sample was 24·2 based on total insects (parasites plus midge emerged and in diapause). The mean in late-maturing crops on the same basis was 14·1 per cent.: this level has little economic significance

Effects of fruit form removals on cotton yields in Central Queensland

During 1957-1959 four trials in both irrigated and rain-grown cotton were conducted in Central Queensland. Removals of all squares and bolls were carried out during eight weeks following the first burst of squaring, approximately three weeks after the appearance of the first squares. Removals during the first four weeks did not affect yields. Maturing of replacement squares following removals during the next four weeks was dependent on length of season and growing conditions. The effect of loss and damage among squares and bolls late in the season was demonstrated by an unusually severe Heliothis armigera (Hubn.) attack during March and the incidence of Pectinophora scutigera (Hold.) during 1958-59

Bionomics of sorghum midge (Contarinia sorghicola (Coq.)) in Queensland, with particular reference to diapause

During 1950-1957 investigations of sorghum midge (Contarinia sorghicola (Coq.) ) were made with respect to hosts, sorghum varietal susceptibilities, life history and seasonal populations, with particular reference to the factors influencing development from diapause

Thrips tabaci Lind. as a seedling problem in Queensland cotton

Investigations on the pest status and population movements of Thrips tabaci in seedling cotton in southern Queensland showed that rapid and extreme fluctuations occurred in samples taken regularly during the growth of a number of sequential plantings. These variations were similar to prior trends in numbers of adult thrips as shown by sticky traps. Populations of thrips in cotton seedlings therefore were more related to external breeding than to actual population build-up in the crop

Life history of the cucurbit aphid (Aphis gossypii Glover)

Studies on the life-history, adult life-span and reproductive potential of Aphis gossypii Glov. on cotton seedlings were made in the insectary at Toowoomba, southern Queensland, in 1965

Biology of the cotton seed bug (Oxycarenus luctuosus (Montr. and Sign.))

The incubation period of the eggs averages between 6 and 7 days and development through the five nymphal stages requires approximately 23 days. Such development will not occur in the absence of seed material of cotton or other host plant. Under laboratory conditions adults lived for periods up to 121 days on dehusked sunflower seed and water

Insecticides for the protection of stored potatoes

In four tests in Queensland in 1966-67, six insecticides were evaluated in dusts against Phthorimaea operculella (Zell.) (terrella (Wlk.)) infesting stored potatoes. In tests with dry potatoes, the percentage infestation 83-85 days after treatment with 0.5% endrin, 1.0% rotenone or malathion (maldison), 2.0% DDT, a mixture of 0.25% pyrethrins with 2.0% piperonyl butoxide, and 2.0% trichlorphon averaged 11.9, 14.2, 14.4, 15.9, 16.4 and 65.6, respectively, in potatoes that were not initially infested artificially, as compared with 70.8% for no treatment. When infested potatoes were deliberately incorporated with those treated, the corresponding percentages were 32.5, 20.2, 29.2, 31.6, 31.7 and 98.2, as compared with 98.9%. In further tests, intended to simulate commercial practice in Queensland, the treatments were applied to freshly dug tubers carrying moist soil (trichlorphon being omitted) and the percentage infestations for no artificial infestation and (in brackets) artificial infestation averaged 12.9 (15.7), 8.4 (8.3), 17.3 (16.2), 7.2 (9.7) and 19.2 (15.8), respectively, as compared with 88.0 (99.3). Endrin is considered too toxic for use on stored potatoes; when malathion and pyrethrins were used, rather more potatoes rotted than with DDT or rotenone, so that rotenone (as derris dust) is recommended for commercial use. ADDITIONAL ABSTRACT: 6 insecticides were tested in 4 trials for the protection of stored potatoes against infestation by the potato moth Phthorimaea terrella. Derris dust containing 1% rotenone was the most satisfactory and performed well with freshly-dug tubers carrying moist soil as well as with dry tubers, including conditions of increased pest populations. DDT 2% dust and maldison 1% dust gave comparable results with dry tubers, but DDT was superior to maldison when applied to freshly-dug tubers. Endrin 0.5% dust was effective in limiting infestation but the toxic nature of this insecticide precludes its use for potato storage. Trichlorphon was inefffective. Rotting of tubers was greatest when maldison was used

Control of aphids in seed potato production

In laboratory trials, demeton-S-methyl was the material most consistent in reducing populations of Myzus persicae and showed the longest residual effect. Endosulphan at 0.06% gave good early kills only