Technical annual report 2000-01
Dept. of Regional Development, Primary Industry, Fisheries and Resources technical annual report; Department of Regional Development, Primary Industry, Fisheries and Resources technical and annual report; Reports; PublicationNT; Technical bulletin (Northern Territory. Dept. of Primary Industry and Fisheries) ; no. 295
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Agriculture -- Northern Territory -- Periodicals; Fisheries -- Northern Territory -- Periodicals
Dept. of Primary Industry and Fisheries
Technical bulletin (Northern Territory. Dept. of Primary Industry and Fisheries) ; no. 295
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Technical Annual Report 2000/01 13 Table 2. 2000 variety performance Variety Name t/ha 1 PAC 442 6.8 2 Hycorn 75 4.2 3 Hycorn 90 6.8 4 DK 689 7.2 5 PAC 269 4.2 6 Pioneer 3237 8.8 7 X32 J35 8.9 8 32 P75 8.0 9 Cracker Jack 6.9 10 Genex 2 7.1 11 PAC 5317 5.6 Machine harvested yields at 12% moisture. Yields in 2000 were reduced because of incomplete pollination. In 1999 mean yield for the site was 9.4 t/ha. In 2000 it was only 6.8 t/ha, a 28% decline from the previous year. It is important to determine why pollination was affected in the 2000 trial and if the chemicals applied interfered with the pollen or silks. Table 3. Insect pests on irrigated maize at DDRF, 2000 Insect pest Growth period and damage Leaf hoppers (various) Cicadulina bimaculata. Possibly also Chiasmus sp. and Orosius sp. From emergence through to week five or six. Causes Wallaby Ear i.e. stunting, distortion and thickening of leaf and veins. Armyworm, Mythimna separata. Late vegetative stage to silking. Defoliate plants and damages flag leaf and silks. GVB, Nezara viirdula. Distortion of cobs and damage to individual kernels. Heliothis, Helicoverpa amrigera/punctigera. Damage to silks and cobs. 2001 Activity: The trial plants were sown on 10 April using a Nodet Gougis precision vacuum planter. Land preparation, experimental design and general management were similar to previous years. Nine varieties were evaluated. Due to heavy infestations of leaf hopper, various lepidopterous larvae and GVB in the past, different insect management and application methods were used. In an attempt to achieve effective control of leafhoppers, all trial seed was treated with Gaucho, a systemic insecticidal seed dressing. Gaucho is one of the newly developed chloronicotinyl chemicals, which has been used in cotton for early season aphid and thrip control. A control area was established to compare the difference between treated and untreated seed. Control of lepidopterous larvae and GVB was undertaken using an Agri-Inject Insectigator III instead of using aerial application. The insectigator injects a precise amount of chemical into the centre pivot line during irrigation. Gemstar (active constituent: Nuclear Polyhedrosis Virus) and DiPel Forte (active constituent: Bacillus thuringienesis var kurstaki) were used through the insectigator to assess the efficacy of these products on armyworm and Helicoverpa spp. when applied through irrigation water. One application of chlopyrifos and one synthetic pyrethroid was applied prior to silking and at early grain fill, respectively, principally to control GVB. At the time of writing this report, only hand harvest yields had been completed.