Bemisia tabaci , also known as the cotton whitefly , has its origin in the regions of primal East Asia . lately , a new biotype ( a new biotype for some taxonomists or a new species for others ) has spread , in a short period of clip , to different European and American neighborhood , causing great passing in the affected harvest . This belligerent biotype appear to have originated in South America and adds to the rigor of the direct damage the endangerment of being a vector of a large number of viruses , some of which impress tomatoes .
Sampling Techniques.
Sampling technique for this species of whitefly can be separate into two groups : those aimed at monitoring unfledged stages and those aimed at adults .
In the cause of adults , sampling technique using adhesive coloring trap have been wide used with in force consequence . Methods have been developed for verbatim works sampling of green stages in both nursery and outdoor crop , with estimation of the relative population or for absence seizure or presence ( binomial sampling ) . In greenhouse crops , this proficiency is fully developed using binomial sampling .
Chemical Methods.
In outdoor crops , controller is fundamentally carried out by chemical method . A encompassing range of a function of pyrethroids ( cypermethrin , deltamethrin , fenpropatrin , fluvalinate , bifenthrin , permethrin , alpha - cypermethrin , cyhelatrin - lambdaa , cyfluthrin , etc . ) present satisfactory levels of efficaciousness and are commend with some geometrical regularity . Growth - regulating products such as buprofecin or teflubenzuron capitalize on chemic control since , in addition to presenting acceptable storey of efficacy , they value born enemy , which in certain areas and clock time of the yr are quite frequent . To control immigrant adult , these product are used in conjunction with endosulfan .
The program of these products must be appropriate , since the potency of the discussion look on it . The fact that the populations are located on the undersurface of the leaves determine the strength of the ware that move by contact , make it advisable to add wetting agents . The covering will be post out when the installation of the pest begins in the new crop and at favorable times for its development . When the crop is forward-looking and the season is not propitious , interventions may be detain . The time between treatments will be reduced if the fly populations can be carrier wave of computer virus . In this case , it will be necessary to take production that are effective in the control of adults , such as endosulfan , as mentioned above .
The strategy for selecting active materials must consider the species ’ ability to build up resistance . As for B. tabaci , the range of usable combat-ready materials is quite limited since biotype B is characterized by its eminent degree of ohmic resistance to many organophosphorus derivative and carbamates . acceptable control are obtain with product such as fepropatrin , methomyl , buprofecin , imidacloprid , and endosulfan .
Biological Methods.
There have been numerous studies over the last 20 years aimed at key natural enemies and alternate methods for chemical control , particularly for its economic consumption in protected crop . This has become more important with the appearance and enlargement of this plague . However , among the natives of Almeria , there are only a few identified natural foe and a few species that have been prove for the biologic mastery of this pest .
Among the predators , it is worth highlight the activity of some species of glitch from the Miridae family that are often associated with cultivation , both outdoors and in the glasshouse . Macrolophus caliginosus , Dicyphus tamaninii , D. errans , and Cyrtopeltis tenuis are active consumers of whitefly larva . Of these , whitefly bio insecticideoffers the best condition for its function in pest ascendency on protected crops . The button in the crop should be done at the beginning of the plague , when the fly populations are low . These species , together with Macrolophus nubilus , They can cause impairment to the plant when populations are high and prey levels are low without have meaning repercussions .
Different species of Anthocoridae ( OOrius laevigatus , O. majusculus , O. niger , O. sauteri , etc . ) occasionally feed on whitefly larva , although their incidence in regulating population seems scarce .
In plants that act as instinctive reservoir , the coleopteran Delphastus pusillus ( Catalinae ) , the dipteran Achetoxenus formosus , and the neuropteran Chrysoperla carnea can seem in significant numbers at certain sentence of the class and throttle the growth of the plague .
When comparative humidity is high , some larvae are bear upon by entomopathogenic fungi . Verticillium lecanii , Paecilomyces farinosus , P. fumosorosus , or Aschersonia aleyridis have been keep apart from whitefly larvae mummies . A prep of the first is market and indicate for use in protected crop , as it requires a high humidness level to infect the larvae .
