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"We have concluded that Pythium spp. cause reduced vigor 

 by killing the feeder roots of peach trees, making them 

 more responsive to stress conditions such as fruit set 

 and prolonged drought and cold." 



"Winter and spring rains produce periodically flooded and 

 saturated conditions in the field. These conditions along 

 with moderately cold temperatures favor build-up, libera- 

 tion, dispersal, and infection by Pythium . Moreover, the 

 flooded and saturated soils are slower to warm., thereby 

 further retarding root growth of host plants. These fac- 

 tors acting and interacting together severely restrict 

 root growth at a time when it is at a premium due to de- 

 mands of bud-break and initiation of flowers and leaf 

 growth. " 



"Factors active in reduction of feeder root systems of 

 peach trees in Georgia include Pythium species, nematodes, 

 and cultural practices." 



"From our data, we concluded that although all three are 

 important, the first step in any control program is the 

 reduction of root injury from discing . Peach trees are 

 shallow rooted and the majority of feeder roots are in 

 the top 8 inches of soil. Discs frequently penetrate 6 

 to 8 inches destroying most of the surface feeder roots." 



" Pythium spp. and nematodes even when present in moderate 

 numbers reduce vigor of peach trees enough to result in 

 greatly increased mortality. They usually operate in an 

 orchard simultaneously. If the Pythium population is lo 

 to moderate, elimination of discing, and a reduction of 

 the nematode population will reduce disease severity." 



"Fumigation will reduce the Pythium and nematode popula- 

 tions so that trees can become established before re-in- 

 fection. " 



"Trees in plots which were solidly tarped after injection 

 of 170 or 200 pounds (per acre) Trizone were larger, 

 more vigorous, and more uniform than those in plots strip 

 treated with 170 pounds of Trizone . Pythium populations 

 were effectively reduced in the strip treatment but build- 

 up was more rapid than in the broadcast treatment." 



In the Section, "Control of Peach Tree Decline in Estab- 

 lished Orchards," 



a. "the single most significant factor in the reduc- 

 tion of tree loss is the elimination of discing in the 

 orchards." (Sinbar was used for weed control) . 



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