In a previous web log post , we talked aboutwhich pesticide can controlThrips parvispinusif you terminate up with an infestation from import plant material .
Buthow do you count on out if this invasive pestilence is in your facilityin the first space ? And , if so , what ’s the best fashion to supervise their population ?
After working with this pest for the last 1 - 2 years , research worker like myselfhave figured out which monitoring methods are most effective . This can help youidentify the problem early , begin a management program , andmonitor the efficacy of your controls .
Figure 1.Thrips parvispinusfemale. Photo by A. Summerfield, Vineland.
Detection and Monitoring inPropagation:
If you ’re produce your own tropical craw , inspecting imported cuttings is unremarkably your first step to detecting unwanted pests . It can also usually give you a look for what the pest pressure is going to be that year ( thinkBemisiawhitefly grownup or nymph in suitcase of poinsettia cutting ) .
However , inspection of mandevilla cutting , as well as the water fromcutting dips , at a commercial greenhouse ( with help from the Buitenhuis lab at the Vineland Research and Innovation Centre)revealed very few adults or larvae . This suggests that most of thethrips are come in on imported industrial plant material as egg .
( Note : this does n’t mean you should n’t dip your cuttings for T. parvipsinus ! Every payload / supplier could be different , anddips also help reduce other coarse pests of tropical crop , such aswhitefly and wanderer soupcon . Additionally , dipping in oil colour can kill thrips eggs ! ) .
Figure 2. Sticky cards in propagation are a necessary tool to detect ifT. parvispinusis emerging from tropical cuttings. Photo by grower cooperator.
So , how do you detect and countThrips parvispinuseggs on your cuttings ? Well … you don’t . Like other thrips species , T. parvipsinusembedded their eggs in folio tissue paper . The eggs are n’t seeable with a hand lens or even with a unconstipated dissecting microscope .
The estimable monitoring method acting is to put alarge amount of yellowed gummy add-in in extension , just above the thinning . Do n’t worry about them getting pissed – sticky cards can still function under overhead watering or at mellow humidness . Especially if the cuttings are sealed in propagation tents , any adult thrip that get stuck on the notice over the next 7 - 14 days are evidence of what ’s coming out of the novel harvest .
If you have a microscope , you may thencover the card with absolved clingstone wrapper and confirm the identify your thrip using thesimple thripid key for growersdeveloped by OMAFRA and the Vineland Research and Innovation Centre . Or , you could send them to a consultant or specialiser who can do this for you .
Figure 3.Damage on new growth (far left) versus damage on old growth (far right) byT. parvispinuson mandevilla.
Monitoring inProduction:
The one sound thing aboutT. parvispinus , is that it seemsVERY host specific . In Canada , we have yet to see damage on crops outside of thetropical plant life specie listed in the table below , even when grow right next to each other . This includes works heel as “ possible ” hosts , such as chrysanthemum , genus Gerbera , bougainvillea and other foliage plants like ferns .
If youaregrowing any of the 8 ornamental legion plants list in Table 1,the first sign ofT. parvispinusyou’ll notice in production will likely be damage(unless you ’re monitoring in generation ) . Damage canshow up differently on different plant metal money , so be conversant with the symptom onyourcrop .
mesa 1.Ornamental crops in North America where significant equipment casualty has been seen fromThrips parvispinus . The likely legion list is much wider , but this pest seems to show a strong server preference for these works specie . Species listed in order of suspected penchant .
Figure 4. Monitoring T. parvispinus using plant taps over a white pan. Photo by OMAFRA.
Damage canalso change by plant emergence microscope stage ( Figure 3).Damage on new growth might first come along as mild tissue paper distortion ( similar to all-inclusive mite or even foxglove aphid)but can advance to thumb or bud miscarriage of the entire meristem under a heavy plague . Damageon honest-to-god growing tend to depend more like heavy mechanical scarring . Interestingly , harm seems to only come out on the upper sides of leaves .
Besides visually inspecting plants for price , your other most important tools for detectingThrips parvipsinusare the same as for other thrips species : plant taps and sticky wag .
Plant Taps forT. parvispinus:
works taps are the most utilitarian tool for monitoringT. parvipsinus , as theygive you a more accurate read of the number of pests in reality on the cropat that moment in fourth dimension ( and not what ’s just been flying around in the general area ) . Also , works taps aregenerally more highly correlated with plant damagethan other grade of monitoring and can help you develop natural process threshold for particular crop and varieties . Here ’s some tips when it occur to carry on plant taps forT. parvispinus .
Sticky cards for T. parvispinus:
Sticky cards can also be a useful tool forT. parvispinusbecause they arevery active flyerscompared to specie like onion plant thrips ( T. tabaci ) and poinsettia thrips ( Echinothrips americanus ) .
However , given the quickly prejudicial nature of this pestilence , cards should not be bank on as the only form of detection . walk the harvest and looking for damage will be much more important for early detecting . However , onceT. parvispinushas already been discover in the crop , cards can be a reliable monitoring which way your population is headed – up or down – depend on your conditions and ascendence bill . As shown in an on - farm trial ( Fig . 5 ) , cards gave us similar information as plant dab in term of pesticide efficaciousness , butthe reply on cards was delayed by a calendar week .
Here are some tips when it come to sticky cards forT. parvispinus .
Figure 5. Monitoring cards generally follow plant-tap trends forT. parvipsinuspressure in mandevilla. However, note that taps indicated thrips numbers went down immediately after chemical sprays, while cards took another week to show this response. Relying only on cards could lead to the erroneous conclusion that chemicals did not work. Data by OMAFRA.
Whether you ’re growing your own product from start to finish , or bringing in finished crop from Florida , monitoring changes a bit at this level . Plant tap would still apply to leaf - only crops like hoya and schefflera . However , T. parvipsinusis powerfully attracted to pollen and nectar . So , for blossom crops , counting adult thrip inside flowers at this stage is a better attack . It will give you a sense of the pressure on the whole works and is much faster than works taps ( and is easier than trying to tap big mandevilla plants or hibiscus “ trees ” ) .
At this point , what terms has been done to the foliage has already belike been done , and there ’s not lead back . But if the issue is mostly the presence of thrips in the bloom before sale , you may want to do a few atomizer with middleman insecticides to exterminate thrips . A threshold of more than 2 - 3 thrip per prime is a good indicator sprays may be need if the merchandise is last out in Canada ( whereT. parvispinuscannot overwinter ) . Thethreshold should be turn over 1 thrips / works if shipping to the U.S. , whereT. parvipsinusis a “ pest of concern ” in all DoS , and is a quarantinable pest in Florida .
Final Thoughts:
finally , if you ’re going to put in all the study of father weekly counts to monitorT. parvispinus(or any other pest!)graphing your data point is a must . We really are optic creatures . Numbers on a pageboy can often be too nonfigurative , and do n’t provide context of what find previously in the crop . Plotting your data , as in Figure 5 , orusing scouting applications likeBugVisionorIPM Scoutekthat can do this for you , can aid you determine the value of card numeration versus plant taps , produce harm thresholds , and make more informed pest management decisions .
Dr. Sarah Jandricic has been the Greenhouse Floriculture IPM Specialist for OMAFRA since 2014 . She impart over 20 years of experience in Floriculture Entomology to the role . you’re able to keep up more of her greenhouse IPM information on ONFloriculture.com .
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Figure 6. A female (left of the flower centre) and male (right of the flower centre)T. parvispinuson a mandevilla flower. Notice that females are dark brown while males are yellow and much smaller. Photo by OMAFRA.
