Remove tape from plant to be evaluated.
Alcohol will dry out skin. Gloves prevent this and may be worn if desired.
Varies with number of plants to be evaluated
| Step | Image |
| Bring plants to be evaluated into the lab. Plants may be loaded onto the bottom section of the cart on their sides. | |
Remove tape from plant to be evaluated. |
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| Write plant number on colored tape on the underside of a petri dish. The dish will follow the sample through the evaluation process. | |
| Carefully remove cage from plant. As the plant comes out of the cage, gather the top third of the plant in one hand. Cut the top third of the plant off. Place the top third of the plant in a Nalgene beaker, cutting into small pieces (see photo). Measure 400 mL 75% ethyl alcohol in a separate beaker. Pour alcohol into beaker containing sample. Make sure all plant material is in the alcohol. | |
| Place removed cage on an empty cart, tape in one green trash can, and stoppers and vials in a second green trash can. Place the soil and remaining plant in a rolling trash can. The pots may be collected in a third green trash can. | |
| Set a timer for 5 min. and place the sample in the shaker bath (set to 150). Keep the petri dish with the sample number on the counter next to the beaker. | |
| After 5 min, pour sample and alcohol onto sieves (coarse screening sieve on top). | |
| Pour a small amount (5-10 mL) into the sample container to rinse any remaining material out. | |
| Pour alcohol in container over sample and allow material to drain for about 1 min. | |
| After sieves have drained, lift the sieves and tilt slightly to drain remaining alcohol. The liquid in the dishpan will be filtered. | |
| Dump plant material in the soil trash can and set sieves aside. | |
| The flask, vacuum hose, vacuum ring, and Buchner funnel should be previously set up. Place thrips screening filter in Buchner funnel and turn vacuum on. Begin by pouring the liquid slowly onto the center of the funnel to prevent liquid from flowing underneath the screening. The remaining liquid can then be filtered. If flow of alcohol through the screen becomes slow, filter remaining liquid through a second funnel and screen. | |
| After filtering all liquid, remove the filters from the funnels and place in the numbered petri dish. Use multiple dishes if necessary. Make sure that multiple dishes all have the plant number and each individual dish is given a letter (a, b, c, etc.) to prevent confusion when counting dishes. It generally works best to have one set of people preparing samples and one set counting. Give the dish and filter to people counting. | |
| Filtrate in the flask may be reused 1-3 times, depending on the amount of chlorophyll extracted into the alcohol. Dark green alcohol should not be reused and may be disposed of in the sink. All items used in sample preparation, with the exception of the vacuum flasks, need to be rinsed with tap water between samples. | |
| Counting of thrips is done by transferring the filter from the numbered dish to a petri dish with lines drawn by a permanent marker. | |
| Place the dish under the dissecting microscope and move the dish to count insects. Record insect numbers on a data sheet. Tally counters are available and may be helpful depending on insect numbers. | |
| All beakers, flasks, etc. used in the evaluation should be washed with soapy water. Thrips screening filters should be rinsed off with DI water and may be soaked in a 1-2% bleach solution if necessary (no longer than overnight). Filters may be placed in the drying oven on a clean pan to dry. | |