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
Made available via the Publications (Legal Deposit) Act 2004 (NT).
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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Department of Primary Industry and Fisheries 226 PROJECT: The Entomofauna of Peanuts (Arachis hypogaea) Project Officers: G.R. Brown and M. Hoskins Location: Katherine and Douglas Daly Objective: To sample and identify insect species found on Arachis hypogaea, and to determine their pest status. To expand on existing data in order to assess those insect species of greatest threat to the development of a peanut industry in the Top End. Background: Peanuts are a high value, high input legume crop. Dryland yields range from 1.3-3.2 t/ha, but supplementary irrigation is recommended for optimum production and quality. Recent crops have been grown under full irrigation in the Dry season. From the time of crop emergence in April 2001, two peanut crops were visited to obtain data. One property is located in the Douglas Daly Basin and the other near Katherine. Both properties use overhead, pivot irrigation and plant one half of each pivot at a time. The Douglas property has two working pivots both being planted to peanuts for four years consecutively. The Katherine property, which has only recently been developed, has grown a first crop of maize and peanuts side-by-side. Method: Beginning in April and continuing until harvest, the Katherine property was sampled each fortnight and the Douglas Daly property once per month. The method of crop sampling has been standardised and is used at various times of crop development to ensure consistency of results. During each field visit samples were taken from five random locations and included vacuum sampling 10 m of crop, visually checking 2 m of crop to especially check for lepidopteran pests and digging at least five whole plants to check for pod damage. Vacuum samples were sorted into pest and beneficial species. Any new insect pests or live specimens that have been collected or reared were lodged in the NT Economic Insect Reference Collection. Results: As the cropping season does not conclude until October partial results are currently available. Complete results, together with a consecutive year of data will be published in 2003. The following is a brief overview of insect pests or potential pests found to date. Sucking bugs (Hemiptera: Pentatomidae) which may be of importance and were seen on the crop, sometimes in large numbers, included the green vegetable bug, Nezara viridula (Linnaeus) and the redbanded shield bug Piezodorus hybneri (Gmelin). Several species of leafhoppers (Hemiptera: Cicadellidae) were also collected. The Brown mirid, Creontiades pacificus (Stal) (Hemiptera: Miridae) and its nymphs were collected but not considered to be at levels capable of causing any damage. Helicoverpa spp. (Lepidoptera: Noctuidae) larvae were present for most of the crops cycle and can be especially damaging at flowering when they tended to feed on flowers instead of foliage. One grower chose to spray on one occasion for Helicoverpa. Spodoptera litura (Lepidoptera: Noctuidae) larvae became damaging at one time in the crop's development, as they began chewing off pegs before they could reach the soil to form nuts. One grower chose to spray for Spodoptera. A number of geometrid and other noctuid moths were found in the crop, the larvae of which had been found feeding amongst peanut foliage or on the ground. No lucerne seed web moths, Etiella behrii (Zeller) (Lepidoptera: Pyralidae) were seen in any samples from either property, however a small amount of damage was found characteristic of internal feeding by a caterpillar leaving only an exit hole.