General Scouting Plan

Walk all rows of the house to be monitored. Inspect each of the rows separately; that is, examine the plants on one side of the row and then walk back in the same row, looking at the plants on the other side.

Scouting for the secondary pests (aphids, whiteflies, worms and downy mildew) and twospotted spider mites in the upper canopy will be done by scanning the plants as you walk each row. Scouting for mites, powdery mildew, Botrytis and stem cankers will be done by inspecting 1 or 2 randomly selected plants per row for a total of 44 plants per 10, 000 square feet of greenhouse area.

Supplies to carry with you include flagging tape, waterproof marker, pruners, plastic bag, handlens and the scouting form on a clipboard with a pen attached.

Definitions

Bend - the location on a shoot where it is bent horizontally and downward

Crown - the woody area at the base of the shoots just above the soil line

Five-leaflet leaf - a rose leaf with five leaflets

Hook - the stub left after a flower is harvested

Lower Canopy - the part of the plant below the crown 

Upper Canopy - the part of the plant above the crown

Monitoring Procedure

 

Protocol for sampling WFT:

Thrips are best monitored with blue sticky cards, set sticky cards in each rose bed to monitor WFT densities on a weekly basis.  Traps must be placed in the center of the bed and maintained from zero to eight inches above the foliage and buds at all times. 
One sticky card should be set for every 5,000 - 10,000 sq. ft.  A minimal sample size of six sticky traps is required from any single greenhouse.  If possible, there should be at least three sticky traps per cultivar sampled. 

Sticky cards should be collected each week and replaced with fresh traps.  The number of thrips per card will then be counted.
A capture of 25 or greater adult WFT on a sticky card in a seven day period translates into an economically threatening WFT flower bud density (mean of two thrips per bud).

 

For sampling other pests:

  Select a number from the random number chart and begin monitoring in that row. Start  with the first number and go through the entire chart before reusing the numbers. This will reduce bias in the sampling.

Begin by walking down the selected row. Scan all plants from the flower to the lower canopy. Look for each of the secondary pests or mites in the upper canopy as follows:

Aphids. Inspect the flower and new growth for aphids. Honeydew, sooty mold and shed skins will alert you to their presence as well.

Whiteflies. Inspect the upper canopy for whiteflies. They occur on the leaf undersides, so the best way to detect them is to look for flying adults or honeydew and sooty mold. Adults can be dislodged by gently shaking the leaf.

Worms. Depending on what species is present, you will see either small holes in leaves (beet armyworm) or leaves rolled with webbing (orange tortrix, omnivorous leafroller.) The larvae will be seen 7 to 10 days after adults are caught in the pheromone traps.

Twospotted spider mites. Inspect the upper canopy for mites above the hook. Stippled leaves and webbing will alert you to their presence. If Persimilis is being used, inspect the crown area as well.

Downy mildew. Sudden defoliation is a common symptom of this disease. Inspect the lower canopy for leaves with angular yellow lesions. Sporulation may be seen on the underside of the lesion.

Use orange tape to indicate the presence of TSSM. For other pests, use a different color and write the pest(s) you have observed on the tape. Use two colors of tape, alternating each week so you will know when an observation was made. Remove old tape each week.

Keep a tally in the ‘Comments’ section of the scouting form if any of these pests are observed.

If only one leaf is affected, remove that leaf and place it in the plastic bag for later disposal.

As you are about                    of the way down the row, select a flower bud about 5 feet ahead of you. This will be the first plant you inspect.

Repeat this procedure                     of the way down the row. This technique will enable you to select plants for inspection before you are close enough to see if they have pests. This will keep the sampling unbiased.

Botrytis. Inspect the flower for Botrytis. Look for circular lesions 1/8 to 1/4 inch across. Check the appropriate box on the scouting form to indicate the presence or absence of Botrytis on the flower.

Powdery mildew. Inspect the five five-leaflet leaves below the bud for live mildew lesions. These will be bright white (dead lesions are a dull white to gray) and sporulation can be seen with a handlens. Check the appropriate box on the scouting form to indicate the presence or absence of powdery mildew.

Stem canker. Inspect the stem and hook for cankers. Look for necrotic, sunken areas on the stem or necrosis of the stub. Either may also have gray to black spore masses. Check the appropriate box on the scouting form to indicate the presence or absence of Botrytis on the hook.

Twospotted spider mite. Inspect the underside of the first leaf above the bend for live mobile stages. Mark the appropriate box on the scouting form to indicate no mites, 1 to 5 mites, or more than 5 mites. Also indicate if more than 15 eggs are seen.

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