Submitted 17 July 00How long does plant material take to pass through the gut of Plutella?
Research at Rothamsted is currently focusing on using Plutella as a model insect for looking at Bt oilseed rape. Part of the research concerns looking at the movement of Cry1Ac through trophic levels, and we thus need to know about plant digestion by Plutella. Does anyone know how long, on average, it takes for plant materail being consumed top pass through the gut and excreted as frass? If someone knows and wishes to release us from the series of experiments for finding out this question, then please e-mail me at guy.poppy@bbsrc.ac.uk.
Guy Poppy, Department of Entomology/Nematology,IACR-Rothamsted, Harpenden, Herts, UK
e-mail: guy.poppy@bbsrc.ac.uk tel: 44 -1582-763133 ex2335 fax: 44-1582-760981
Posted 15 July 00:
Autodissemination for control of DBM
Entomopathogenic fungi such as Zoophthora radicans can contribute to the natural regulation of DBM populations. The concept that Z. radicans could be introduced into DBM populations via sex pheromone traps ('autodissemination') has potential in IPM. Male moths would be attracted into specially designed fast entry slow exit traps in response to synthetic female sex pheromone. Whilst inside the trap they would become contaminated with infective conidia (spores) from a sporulating source of Z. radicans. On habituation to the pheromone, contaminated moths would leave the trap and return to the crop disseminating the pathogen amongst their own populations.
As a pre-cursor to large scale field trials this hypothesis was tested in a caged population of DBM in Australia. Adult male moths derived from a laboratory culture were contaminated with conidia of Z. radicans and released into a 16.4 m x 16.4 m field cage containing 550 DBM-infested broccoli plants. Infected larvae were first detected on these plants four days after initial release of the adults and after 14 days 20% of all sampled larvae and pupae were infected. At the final survey, 48 days after initial release, the proportion was 79% (93% amongst 3rd and 4th instar larvae). Thirty five days after release infected larvae and pupae were detected on control plants. These had been individually contained within poly-organza covered cages inside the large field cage and thus could not have been contacted by contaminated adults. This result, together with the detection of Z. radicans conidia on microscope slides exposed within the large field cage suggest that aerial transmission is a contributory factor in the spread of the fungus.
Richard Vickers
CSIRO, Entomology, Long Pocket Laboratories PB 3, Indooroopilly, QLD 4068, Australia
e-mail: r.vickers@brs.ento.csiro.au tel: (07) 3214-2824 fax: (07) 3214-2885Judith Pell
IACR-Rothamsted, Ent. and Nematology Dept., Harpenden, Hertfordshire AL5 2JQ, England, UK
e-mail: Judith.Pell@bbsrc.ac.uk
Submitted 11 July 00
An article has been published recently concerning a research project on biological control of Plutella xylostella in France. The paper is entitled "Ability of 17 strains of Trichogramma to control Plutella xylostella L. (Lep.: Yponomeutidae), in the laboratory", Tabone et al, 1999, Ann. Soc. Entomol. Fr., 35: 427-433 (in French). Studies are still underway for testing other indigenous and exotic strains. In the same time, knowledge about the biodiversity of the natural enemy complex of Trichogramma sp. will be included. The laboratory screening aimed at selecting the best strains to be tested in the field in order to evaluate their potential as biocontrol of DBM.
Elisabeth Tabone
INRA, Entomologie et Lutte Biologique, 37 Bd du Cap, 06606 Antibes, France
e-mail: tabone@antibes.inra.fr Tèl: 04.93.67.88.99 Fax: 04.93.67.88.98
Submitted 11 July 00
Egg parasitoids, DBM and row covers in Japan
In Japan, cruciferous leaf vegetables are often covered with cheesecloth and nonwoven fabrics to control pest insects. This is termed "row covers". But, diamondback moth adults sometimes intrude into such row covers and cause damage to the vegetables. Since an egg parasitoid, Trichogramma chilonis, could pass through the cover mesh, DBM was efficiently controlled by row covers together with the egg parasitoid.
Izumi Ohta
Laboratory of Insect Pest Control, Chugoku National Agricultural Experiment Station, 6-12-1, Nishifukatsu, Fukuyama 721-8514, JAPAN
e-mail: ohtaiz@cgk.affrc.go.jp tel:+81-849-23-4100 fax:+81-849-24-7893
Submitted 29 Jun 00
Nosema spp., antibiotics, infection rates, and Diadegma spp.1. We found that Nosema spp (most probably N. bombycis) is resistant to Fumidal-B, the antibiotic commonly added to artificial diet of DBM, even at increased concentration. This was tested together with other antibiotic, albendazole, tetracycline and Suprim. Adding albendazole at the same concentration as Fumidal-B supressed the spore production, and thus reduced disease infection.
2. We also found that Nosema disease infection rate was higher in the highland (lower than 20°C) than in lowland (>30°C) due to temperature difference. Surprisingly, parasitoids of DBM were abundant particularly the Diadegma semiclausum, indicating they were not really affected by this disease infection.
Idris Bin Abd. Ghani
School of Environmental and Natural Resource Sciences, Faculty of Sciences and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, MALAYSIA
e-mail: idrisgh@pkrisc.cc.ukm.my
Submitted 20 June 00
An article on the possibility of using Indian mustard as a trap-crop for DBM in South Africa will be appearing in the journal Crop Protection soon. Details (the issue and page numbers etc.) will be posted when they are available.
Deidre Charleston
Insect Ecology, Rietondale Plant Protection Research Institute, Private Bag X134, Pretoria, South Africa
e-mail: rietdi@plant2.agric.za tel: +27 (0)12 329 3269 fax: +27 (0)12 329 3278 cell: +27 (0)82 962 5588
Posted 14 June 00
At the beginning of this year, many from around Australia participated in a Diamondback Moth modelling Workshop in Brisbane. A prototype simulation model using DYMEX software was produced and the interest group that has been formed is continuing with research to improve the model and its predictions. The site can be accessed at:
http://www.ento.csiro.au/research/pestmgmt/IPMModellingNetwork/index.htm
Posted 20 April 00
Chemical sprays and Cotesia occurrence in the Mekong Delta
I was recently in Cambodia and was shown cabbage fields where Cotesia plutellae had been released (by AVRDC) for control of DBM a few years earlier. In fields where chemical sprays were not used (although one Bt spray was applied), the cabbages sustained very little damage. I counted as many as 4 Cotesia coccoons on one plant. An adjacent field where chemical insecticides (mixtures of several things) the cabbages were heavily damaged by DBM (no Cotesia were found).
This was a lowland situation in the Mekong Delta region in the Kien Svay District near Phom Penh.
Merle Shepard
Professor of Entomology and Resident Director, Coastal Research and Education Center, Clemson University, 2865 Savannah Highway, Charleston, South Carolina 29414, USA.
e-mail: mshprd@CLEMSON.EDU Phone 843-766-3761 Fax 843-571-4654