Literature: Economic Thresholds

Economic Thresholds

Blackshaw-RP; Coll-C; Humphreys-IC; Stewart-RM
The epidemiology of a new leatherjacket pest (Tipula oleracea) of winter cereals in northern Britain.
HGCA-Project-Report. 1996, No. 120, 119 pp.; 7 pp. of ref.
A study of protein bands indicated that Tipula oleracea (rather than T. paludosa) was responsible for autumn damage to cereals in northern Britain during outbreaks in the mid-1980s. A survey showed that 84% of the damaged cereal crops had been preceded by a winter oilseed rape crop. In a comparison of sampling methods, brine flotation was found to be the most effective and easiest to use in arable crops later in the season, although unreliable on newly cultivated soil. Samples collected from winter oilseed rape and nearby fields of winter wheat yielded larvae in 20% of rape fields, but none in wheat in November. In spring, larvae were found in wheat, but more were found in rape fields. By September they were detectable in 73% of rape fields. Laboratory studies showed that larvae of T. oleracea could survive on oilseed rape and grew faster on rape than on wheat. Field experiments showed that the closed rape canopy at the time of the first flight period of the tipulid (May/June) impeded vertical movement of the adults but not horizontal movements. It is concluded that the introduction of oilseed rape into arable rotations has created this pest problem in winter wheat. Sampling rape stubble before cultivation for sowing wheat is recommended.

Blackshaw-RP
Leatherjackets in grassland.
Strategies for weed, disease & pest control in grassland: practical implications of recent developments and future trends. Proceedings of the British Grassland Society conference held on 27 February 1991 at Hatherley Manor Hotel, Gloucester. 1991, 6.1-6.12; 40 ref.
The biology and ecology of the tipulid pests of grassland are considered in relation to their pest status in the UK. There are 5 main tipulid species (all Tipula spp.) in the UK, of which only T. paludosa and T. oleracea are recognised pests, with T. paludosa being the most important. Climatic conditions are more important to population regulation than the effects of natural enemies, but the way in which they operate varies by region. Damage to grassland starts in September and builds up over the winter and spring. Insidious losses are more important than sward destruction. Good control is easily obtained with insecticides, with minimal effect on nontarget organisms, but identification of fields that could benefit from treatment remains a problem.

Blackshaw, R.P.
Resolving economic decisions for the simultaneous control of two pests, diseases or weeds.
Crop protection. 5, no. 2 (Apr 1986): p. 93-99.

Blackshaw,-R.P.
A preliminary comparison of some management options for reducing grass losses caused by leatherjackets in Northern Ireland.
Ann-Appl-Biol. London : Association of Applied Biologists. Oct 1985. v. 107 (2) p. 279-285. ill.

Blackshaw, R.P.
The impact of low numbers of leatherjackets on grass yield.
Grass and forage science. 39, no. 4 (Dec 1984): p. 339-343.

Coll-C; Blackshaw-RP; Clarke-JH (ed.); Davies-DHK (ed.); Dampney-P-MR (ed.); Froud-Williams-RJ (ed.); Griffith-PJ (ed.); Lane-A (ed.); Sim-L (ed.); Stevens-DB
Leatherjackets in winter cereals: a self-inflicted problem?
Rotations and cropping systems, 16-18 December 1996, Churchill College, Cambridge, UK. Aspects-of-Applied-Biology. 1996, No. 47, 145-151; 8 ref.
Large, local aggregations of Tipula oleracea larvae were found damaging winter cereal crops from October onwards in NE Scotland, UK. Results from field surveys established that cereal crops following oilseed rape in the rotation were most at risk. Larvae were found overwintering in oilseed rape crops and in crops which followed oilseed rape in the rotation, but not in fields which had not included oilseed rape as part of the rotation. Data collected from emergence traps showed that overwintering larvae emerged as adults in early summer. It was shown that adult flies could not escape from the canopy of the oilseed rape once flowering was complete. Flies trapped beneath the canopy could continue to mate and oviposit underneath the crop canopy and consequently, this could lead to the appearance of large, local aggregations which partly explains the presence of significant populations of larvae in following crops of winter cereals.

Jackson, D M.
European crane fly (Tipula paludosa) an introduced pest of turf and pasture in Whatcom County, Washington.
Proc Wash State Entomol Soc (MAR 1973): 356-358.

Jackson, D M. ; Campbell, R L.
Biology of the european crane fly, Tipula paludosa Meigen, in western Wasthington (Tipulidae; Diptera)
Tech Bull Wash Agric Exp Stn 81 (JULY 1975): 23 p. map. ref. Publishing Agencies: Experiment Station

This site is hosted by:

Questions, comments and contributions directed to Todd Murray or Sharon Collman