DIAGNOSTIC UPDATE 



During the next few months 

 we can expect to see the typical 

 problems in greenhouse crops 

 (root rots, botrytis blight and 

 CANKER, and iNSv). Root rots are a 

 common problem occurring on a 

 wide range of plant material in- 

 cluding poinsettias and gerani- 

 ums. Plants showing symptoms of 

 nutrient deficiency, marginal 

 browning of the leaves, stunting, 

 or wilt should be considered sus- 

 pect. Remove the plants from the 

 containers and check the roots for 

 brown or black lesions or water- 

 soaked, mushy roots. Severely in- 

 fected plants should be discarded. 

 Poinsettias should be scouted for 

 powdery mildew. Check the 

 lower leaves for chlorotic (yellow) 

 spots on the upper surface with 

 powdery colonies on the lower 

 surface, below the chlorotic areas. 

 Infected leaves should be re- 

 moved immediately (put them in 

 a plastic bag) and a spray pro- 



gram begun. The remaining plants 

 should be treated with a fungi- 

 cide drench. Remember that sani- 

 tation and good air circulation are 

 the best preventative measures for 

 preventing diseases in greenhouse 

 crops. 



TURF 



Because the month of June re- 

 mained cool and wet through the 

 third week, spring diseases such 



as FUSARIUM PATCH, ANTHRACNOSE 



(mostly in the crown rot stage), 

 and RED THREAD predominated. In 

 early July we moved almost over- 

 night into hot, humid weather 

 with its typical diseases: brown 



PATCH, ANTHRACNOSE, and SUMMER 



PATCH. Necrotic ring spot and 

 CROWN rots resulting from leaf 

 spot fungi appeared quickly on 

 lawns (especially sodded lawns), 

 causing considerable damage. 

 With a return to cooler, moist fall 

 weather, we can expect to see the 



reappearance of red thread and 

 leaf spots. Now is the time to be 

 thinking about renovation with 

 species and cultivars of 

 turfgrasses that are less suscep- 

 tible to diseases. Mid-October 

 through November is also the time 

 that preventative fungicides should 

 be applied for snow molds. 



If you wish to submit plant mate- 

 rial to the UNH-PDL for diagnosis, 

 send samples (with a check for 

 $12.00) to: The UNH Plant Diag- 

 nostic Lab, C/O Dr. Cheryl Smith, 

 Plant Biolog}/ Department, 241 

 Spaulding Hall - UNH, Durham, 

 NH 03824. Samples should be ac- 

 companied by an identification form 

 (available from your county Coopera- 

 tive Extension office or by calling 

 862-3200). Cheryl Smith is the UNH 

 Cooperative Extension Specialist in 

 Plant Health, and can be reached at 

 (603) 862-3841, e-mail: cheryl.smith 

 ©unh.edu. 



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