Tag: floriculture research

Consumers want “bee friendly” plants, not “neonic-free”

For those of you who missed the summary on Floral Daily,  an interesting study on pesticide labeling of ornamentals was just published by researchers and extension specialists at Michigan State University(1).

The MSU team found that people who buy ornamental plants (both indoor and outdoor) obviously want healthy, insect-free plants.

But, they also found that consumers value plants labelled specifically as “bee friendly”.  Consumers in the study were willing to pay anywhere from $0.13 to $1.50 more per plant for “bee friendly” plants  than those labelled “grown without neonicotinoid insecticides“.

Bee foraging on a landscape plant. Photo by Dr. Elsa Youngstead, NCSU.
Bee foraging on a landscape plant. Photo by Dr. Elsa Youngsteadt, NCSU.

Given all the hubbub about neonics in particular, why didn’t “neonicotinoid-free plants” resonate with consumers?  Well, it turns out many consumers don’t actually understand the term.  Of the >2000 people interviewed in this study, 57% admitted outright they didn’t know what it meant, and 11% thought the term meant produced would any insecticides.  The MSU researchers found that labeling a plant as “neonicotinoid free” may actually have a detrimental effect on purchasing.

Plant tag from a major store indicating the use of neonicitinoid insecticides.
Plant tag from a major store indicating the use of neonicotinoid insecticides.

Studies like this are timely, considering major box stores (Home Depot, Loblaws, etc.) are demanding labeling to satisfy public concerns.    Information on which labels consumers best respond to can be used by growers  producing their own labels.  Additionally, this information can be factored into pest management decisions.

1. The original article can only be obtained through a University library subscription or by purchase from HortScience, here: http://hortsci.ashspublications.org. Or, I can tots get you a copy if you really want one.

 

When “harassment” is a good thing in your greenhouse

Well, now that I’ve gotten your attention, let’s be clear that I’m talking about bugs, here, people.  Specifically, Western flower thrips and predatory mites such as N. cucumeris and A. swirskii.

L2 western flower thrips next to a predatory mite egg (left) and 2 adult mites (right).
Second instar (L2) western flower thrips next to a predatory mite egg (left) and 2 adult mites (right). Photo credit: Sarah Jandricic.

We all know that predatory mites only kill and eat the small, first larval stage of thrips (referred to as L1’s).  Larger life stages (i.e. L2’s and adult thrips) are simply too large for the mites to kill.

But, that doesn’t mean they don’t help control them.

Predatory mites will repeatedly attempt to kill L2 thrips – attacking them up to  40 times an hour (1). The L2 thrips are able to fend off these attacks by either running away, or “slapping” mites in the face with their abdomens.  You can watch the hilarity that ensues when mites attempt to attack too-large thrips larvae here.

But this “harassment” by mites takes it’s toll on thrips.  Because thrips spend more time fending off mites, they spend 30% less time feeding (2).  Over time, this translates to 40% less damage on plants with predatory mites, compared to no mites (2).  And, the presence of mites can reduce survival of L2 thrips by up to 78% (1), probably because eating less means the thrips lack the nutritional reserves to complete development.

And all of this is accomplished just through “intimidation” of thrips by mites – not through consumption.  Scientists term these “non-consumptive” effects, and we are just starting to learn the importance of these effects in biological control.  Research is now suggesting that non-consumptive effects like “harassment” may actually account for 50% of the pest control we see in greenhouses (3).

This makes sense with our thrips example.  Not only do mites reduce the feeding and survival of larval thrips, but ongoing research from Cornell University  shows that the presence of mites reduces the number of eggs laid by adult thrips, and shortens adult thrips lifespan (4).  Even the presence of predatory mite eggs on a plant has been shown to  “scare” L1 thrips into eating less, according to research from Austria (5).

And, it would make sense that the more mites you have, the higher the number of “scary” encounters thrips will have with them, improving control. 

So, lets give a hand to the hard working, harassing, predatory mite, who’s doing more than we ever thought in floriculture IPM.  Stay creepy, little guys. Stay creepy.

References: (1) Jandricic, S.E., Schmidt, D., Bryant, G., and Frank, S.P, NC State University. Unpublished data. (2) Jandricic, S.E. and Frank, S.P.  2014.  Too scared to eat: non-consumptive effects of predatory mites.  IOBC/wprs Bulletin 102: 111-115; (3) Preisser, E. L, Bolnick, D. I., & Benard, M. F. 2005: Scared to death? The effects of intimidation and consumption in predator-prey interactions. Ecology 86: 501-509. (4) Loughner, R., and Nyrop, J.  Cornell University. Unpublished data. (5) Walzer, A., & Schausberger, P. 2009: Non-consumptive effects of predator mites on thrips and its host plant. Oikos 118: 934-940.