Weekend IPM Blog

By: Laura and Alyssa

October 19-21, 2012

Laura and I were asked to release half of the biological controls into the greenhouse, this included 25 Biobest cards, and 25million Nematodes. The Biobest cards contain the larva of Eretmocerus eremicus and Encarsia formosa, these are both considered to be parasidic wasps that attack 2 different types of whitefly. Encarsia are the black larva and these hatch and attack the greenhouse whitefly, while Eretmocerus attack the silverleaf whitefly. The Nematodes were being released to control the fungus gnat problem. Both of these controls are to be stored in to refrigerator until they are ready to be used, this is because the Biobest cards will begin to hatch when exposed to the temperatures in the greenhouse, and the nematodes will become useless if they are heated to room temperature.

 Friday we observed the Biobest cards before placing them throughout the greenhouse to see the before image of  the larva.

Friday was also a good day for us to apply the nematodes, we concluded this based on the information that the media would need to be fully saturated for the nematodes to activate and function properly. We mixed 25 million nematodes (half of the container) with 10L of temped water, and stirred the solution continuously, this is also an important step to ensuring that the nematodes work properly, we applied 20ml of the nematode solution to each poinsettia.

Saturday we decided to pull a few of the Biobest cards off of the crop to observe if any of the larva had begun to activate, in doing this we found that some of the Eretmocerus had begun to emerge where as we were unable to find and specimens of the Encarsia emerging. We took a few pictures of the Eretmocerus emerging.

We then began our search of the sticky strips in hopes of finding both whitefly specimen’s, we found a greenhouse whitefly and a silverleaf whitefly on the sticky strips.

We then did research on symptoms of whitefly and found that suckering of leaves can often be caused by the whitefly eggs, we pulled a few leaves that had these symptoms. Using the 140x camera we found both freshly laid and mature eggs of the greenhouse whitefly, we concluded that that white to transparent eggs were freshly laid whereas the mature eggs are brown or black in colour.

Finally the biggest moment in our IPM research was finding a pupa of the silverleaf whitefly on the backside of a ‘Polar Bear’ leaf. The bug book described the pupa as being yellow/transparent with red eyes, often found in a profile view, where as the greenhouse whitefly pupa has a more flattened appearance.

In the end our opinion is that the biobest cards would most likely work a lot better if storage is made a priority because if they aren’t it degrades the quality of the cards, which in turn affects the number of pests present in our greenhouse.

Furthermore we feel that there needs to be a better way to add the 20ml of nematodes to the pots; using measuring cups does not allow the distribution to be exact, which again affects the number of pests we have to deal with.

We also can confidently say that both types of whiteflies are still present in the greenhouse.