-J*- 



problems is very difficult and 2) the crop becomes 

 very sensitive to pesticide applications after the 

 bracts color up. Spraying after bract coloring might 

 control the pests, but injure the crop and severely re- 

 duce its salability. Never allow the plants to become 

 heavily infested. The idea is to keep them clean. 



■ COMPLETELY ELIMINATE UNDER-BENCH WEEDS. 

 Plants that grow under the benches are not hit by 

 pesticide applications, so they serve as refuges for 

 aphids, whiteflies and other insects. 

 From this spot, the insects can keep 

 reinfesting your crop. Out of sight, 

 out of mind! 



with whom we worked 



■ ELIMINATE VEGETATION GROW- 

 ING WITHIN FIVE FEET OF THE 

 GREENHOUSE EXTERIOR. You may 

 wish to use mulch or gravel to keep 

 plants from growing in this area. In- 

 sects that live on them are easily 

 sucked into the greenhouse through 

 vents and doorways If elimination 

 is not appropriate, keeping the veg- 

 etation low may help. Do not mow 

 vegetation near the vents when fans 

 are on and air is being sucked in. 



were able to produce crops 



that were almost entirely 



free of whiteflies 



T*r Jnspect all plants and cuttings immediately upon 

 arrival. This will allow you to reject those that are in- 

 fested, before they spread. Upon arrival, place them 

 in a "quarantine" area — one removed from your other 

 plants, so they are protected while you examine the 

 new arrivals. Many cuttings arrive with low numbers 

 of whiteflies. A few shipments are badly infested. 

 Probably few shipments are completely clean. Take the 

 time to examine the undersides of leaves, preferably 

 with a magnifying glass or hand lens. An hour or two 

 now could save much time later, 

 and avoid costly problems. If re- 

 jecting the shipment is a difficult 

 option, at least you can treat the 

 incoming material with an appropri- 

 ate pesticide before the problem 

 spreads. 



the growers 



at the time of sale. 



■ "PET" PLANTS. Plants that stay 

 in the greenhouse year after year 

 (your favorite potted orange tree, 

 for example) may serve as refuges 

 for thrips, whiteflies, aphids, fungus 

 gnats, or other pests. Removing 

 them from the poinsettia house will 

 insure they won't spread pests to 

 your poinsettias. 



■ CONSIDER SCREENING ALL VENTS. Data from 

 sticky cards last year strongly demonstrate how many 

 insects are sucked into the greenhouse during ventila- 

 tion. When venting stopped, the number of insects 

 on the cards dropped sharply. This drop also oc- 

 curred after the first good frost. Covering vents with 

 fine screening (400 holes per square inch) will prevent 

 virtually all insects from getting through. You may 

 have to increase your fan size to compensate for re- 

 duced air flow or build frames around the vents to in- 

 crease the screened area. 



■ DISCOURAGE WORKERS FROM WEARING YELLOW 

 OR YELLOW-GREEN CLOTHING. Winged stages of 

 aphids and whiteflies are strongly attracted to these 

 colors. Wearing such clothing can cause workers to in- 

 advertently carry insects from one section to another. 



■ MONITORING WHITEFLY POPULATIONS IS VALU- 

 ABLE. Regular checking will allow you to maximize 

 the effectiveness of insecticides applied for whitefly. 

 You can tell when and where treatments are needed, 

 determine if sprays have been effective, aiid tell when 

 treatments are not needed. The most effective pro- 

 gram includes both sticky cards and plant inspections. 



Yellow sticky cards are commercially available and 

 easy to use. We set them on bamboo stakes. As the 

 plants grew, we kept the cards just above the canopy. 

 Yellow sticky cards only tell us where adults are (and 

 therefore where to expect egg laying). We followed 

 (adults!) whiteflies, aphids, shore flies, fungus gnats 

 and thrips with the cards. One card for no more than 

 1000 square feet of production area is recommended. 

 We checked weekly, but more frequent checking is 

 more helpful. 



Renters Oiarben (£,m\et Jnc. 



656 South Mammoth Road (Rte. 28A) 



Manchester, Nfl 03109-5049 

 (603) 625-8298 • Fax (603) 622-4073 



Nursery • Greenhouses 

 Craft & Christmas Shop 



We Support The Plantsman 



Since 1890 

 allyourneeds: 



at^c/u'm 



P.O. Box 160. King <y Prussia. PA IS 

 (Z1S)26S-4200 



SCOTT A. STEWART 



.MA 01864 

 Ptwna: 306-664-0006 



nUC 506-664-4076 



