To get good restraint of whitefly in Poinsettia crops , include the repellent Bemisia biotype , Biobest IPM , and Pollination Specialist Koen Merkus explicate the grandness of keep the population level below a ‘ tipping point ’ by belated October and how to do it .
Whitefly is the most economically crucial pest of Poinsettia , with two character far-flung in European and North American crops – Trialeurodes vaporariorium glasshouse whitefly and Bemisia tabaci – unremarkably call Silverleaf , sweet potato , or tobacco whitefly .
Both whitefly species feed on plants , reducing vigor and excreting a embarrassing honeydew melon which attracts unsightly sooty molds . In addition , Bemisia can vector potentially devastating plant virus - importantly reduce vendible payoff .
Two Bemisia biotypes“Within the Bemisia population , there are two biotypes – Bemisia MEAM1 ( formerly known as B type ) and Bemisia MED ( formerly known as Q character ) , ” explains Koen . “ The latter is more insubordinate to chemical insecticides but , on the plus side , see it more difficult to witness a teammate and reproduce . ”
“ So , in the circumstances without high insect powder pressure , Bemisia Q biotype is out dwell by Bemisia B biotype . However , frequent coating of chemical insecticide can wield a selective upshot , favour the resistant biotype . If at an other stage in the crop , this can lead to pregnant problems later on . ”
If Bemisia is present in a Poinsettia harvest , Koen says it is safe to assume both biotypes will be found . “ It is unacceptable to tell them aside visually – they can only be identify through molecular analytic thinking , ” he says .
Tipping pointHe give way on to explain there is a tipping breaker point . “ By the end of October , agriculturist should aim for an infestation stage below 20 % - i.e. , fewer than one per five plant . A higher population layer is likely to cause number down the business line , and subsequent chemical sprays will favor the Q biotype . Therefore , a preventive approach is all-important . ”
Start cleanTo keep glasshouse and baccy whitefly populations in check , Koen try the grandness of start the Poinsettia craw clean and stay extremely vigilant . This start by inspecting cuttings carefully on arriver from the propagator .
“ Having sticky trap in space before the cuttings arrive means monitoring starts immediately , ” he articulate . “ If whitefly is present , it will often be find promptly . ”
“ Careful scouting is vital – ideally , find fault up random press clipping and audit the bottom of the leaves . ”
“ If the pestilence is detected at this early stage , it ’s prudent to spray . If the initial whitefly population is high-pitched early on , growers stop up playing ‘ see up ’ with their control scheme throughout the product cycle . take action early saves a whole portion of trouble subsequently . As the plants are still small , good spray reportage can be accomplish at this stage . ”
Before sticking the slip , he recommends dip them in Preferal WG - a biological insect powder for whitefly controller .
Pot spacing“A week before the stuck cut are spaced , introduce Amblyseius swirskii mites ( Swirskii - System ) and supplemental feed with Nutrimite ™ , ” he apprize . “ With the potentiometer intimately spaced , the mites can move around easily and are less likely to be lost . ”
At the point the sight are spaced , Koen advocate pop weekly introduction of Eretmix - System containing a compounding of two parasitoids ; Encarsia Taiwan ( Encarsia - System ) for controlling glasshouse whitefly and Eretmocerus eremicus ( Eretmocerus - System ) to target Bemisia . In addition , he says it may be necessary to introduce further Swirskii - System corroborate by Nutrimite ™ .
“ We strongly recommend using both merchandise , ” enounce Koen . “ The swirskii aim the first instar of the whitefly , while the parasitoids point the 2d to quaternary instar . This minimizes any possible intraguild challenger between beneficials . ”
tote up up , Koen says , “ the key is to supervise and scout closely to start the crop clean and , if possible , to review last season ’s scouting data . Then employ a full IPM scheme - involving parasitoids , a predatory mite , and bioinsecticides to keep the Bemisia universe below the 20 % tipping point . Be aware that whitefly pressure may also dissent per variety . ”
For more information : Biobest Group NVT : +32 14 25 79 80[email protected]www.biobestgroup.com
