Re: [CH] Pepper huasteco begomovirus

Ron Hill (rontah@enigma71.freeserve.co.uk)
Fri, 07 Apr 2000 18:43:27 +0100 

At 12:08 07/04/00 -0400, you wrote:
>How is this vectored? (spread)
>Seed, insects or soil?
>
>TIA
>Byron

Hi Byron,
 
This was one item that Google turned up.
(Bemisia is the transmission agent.)

The tobacco whitefly Bemisia tabaci poses a real threat for growers of
greenhouse
  crops in Europe. It is a relatively new pest, accidentally introduced from
the USA.
  The whitefly causes direct damage to plants by its feeding activity, and
indirect
  damage due to the production of honeydew and transmission of plant pathogenic
  viruses. Biological control of this pest is therefore needed, the more so
because
  chemical control is declared undesirable by the Dutch government in its
Multi-Year
  Crop Protection Plan. Several natural enemies of B. tabaci are nowadays
used in
  practice. The parasitoid Encarsiaformosa, successful in controlling
another whitefly
  species in greenhouses, is less successful in controlling the tobacco
whitefly. Other
  natural enemies currently used are insect predators, but these species are
either
  expensive, or generalistic, or both. Generalist predators are less
suitable natural
  enemies because they can also attack the natural enemies used against
other pests,
  thereby hampering their control.
  In this project we will search for natural enemies in the group of
predatory mites
  (Phytoseiidae). Predators from this group have a history of success in
biological
  control programs. Several species are successfully used against various
pests, such
  as spider mites and thrips. Advantages of predatory mites are that they
have high
  population growth rates, they are cheap and easy to rear, and that they
are more
  specialistic natural enemies than the insect predators mentioned above.
Another
  advantage is that many predatory mite species can use plant-produced
pollen as a
  food source, and can thus even persist in crops when no pest is present.
Some 11
  species of phytoseiids are known to be associated with whitefly, and 3 of
those are
  currently available at the University of Amsterdam, whereas the remaining
species
  will be obtained in the near future. The current proposal aims at
evaluating these
  species as biological control agents in greenhouses, using the following
criteria: 

  1.Their capacity of killing local whitefly populations. 
  2.Their efficiency at detecting whitefly populations. 
  3.Their compatibility with other natural enemies. 
  4.Their ability to control whitefly throughout a greenhouse. 
  5.Their ability to use pollen as a food source. 
  6.Their ability to control the other whitefly species, Trialeurodes
vaporariorum.