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STONE FRUIT WEED CONTROL 



Bradley A. Majek 



Assistant Specialist in Weed Control 



Rutgers Research and Development Center, Bridgeton, NJ 



A good orchard floor management program eliminates and prevents the 

 reestabi i shment of undesirable vegetation. Weeds compete with fruit trees 

 for water, nutrients and light, serve as alternate hosts for diseases and 

 harmful insects, harbor rodents, and impede harvest. Herbicides used to 

 control weeds must have a good margin of crop safety to minimize the risk to 

 the tree. 



Weeds can be classified by life cycle. Annual weeds live less than one 

 year. Summer annuals germinate in the spring or early summer, grow, flower, 

 produce seed, and die in the fall. Winter annuals germinate in late summer 

 or in the fall, grow vegetatively through the fall, overwinter, flower, pro- 

 duce seed, and die in the spring. Biennial weeds live more than one year 

 but less than two years, produce seed, and die. Perennial weeds live more 

 than two years. They often reproduce vegetatively as well as by seed and 

 are much more difficult to control. Consider summer annuals, winter annuals 

 and biennials, and perennial weeds separately when planning a control 

 program. 



Weed control in a newly planted orchard should be planned to provide a 

 maximum margin of crop safety. Established biennial and perennial weeds 

 should be controlled by tillage and/or herbicides prior to planting. After 

 planting, use a combination of napropamide (Devrinol^) OR oryzalin (Surf Ian") 

 OR pendimethal in (Prowl'^) for annual grass control PLUS oxyfluorfen (Goal") 

 for control of broadleaf weeds. Apply in early spring after 1 to 2 inches 

 of rainfall or irrigation has settled the soil around roots of the newly 

 planted trees, but before weeds germinate or tree buds break. Do not 

 cultivate or mechanically incorporate Goal"^ into the soil or effectiveness 

 will be reduced or eliminated. 



Additional herbicides are available in established, bearing orchards. 

 Terbacil (Sinbar^ and diuron (Karmex") used alone or in combination are 

 extremely effective herbicides, but use is restricted to established 

 orchards. The margin of crop safety observed with Sinbar" or Karmex" is 

 narrower than that for herbicides recommended for use in newly planted and 

 one-year-old orchards. Sinbar or Karmex" should not be used on loamy sand 

 soils or soils with less than 1^ organic matter. Consider using Devrinol^, 

 OR Surflan^ OR norflurazon (Sol icam^^) PLUS Goal'f' OR Princep"'^ or reduced 

 rates of Sinbar^ OR Karmex^ on sites with extremely coarse textured soils 

 low in organic matter for summer annual weed control. 



