Orchard Floor Management to Optimize Pear Fruit Finish
Glenn McGourty, Mendocino Co. Farm Advisor
UCCE Mendocino Cnty, Ag Ctr/Courthouse Ukiah, CA 95482
Weed surveys conducted by McGourty and Lindow have determined that great differences exist between bacterial populations living on the surfaces of these plants. Two bacteria in particular affect pear fruit culture. Pseudomonas syringae serves as an ice nucleator. Large populations of the organism on the surface of plants can cause frost formation at high temperatures (31-F) than when the bacteria is not present (29-F). Erwinia herbicola causes fruit russeting by colonizing the lenticels of the fruit, and producing indoleacetic acid (IAA). 1000-fold differences in bacterial numbers are common, with grasses and tender annual weeds having very large numbers, and plants with waxy cuticles (legumes especially) having much lower numbers.
Experiments conducted in a commercial pear orchard in Hopland,
CA demonstrated that fruit packout was significantly affected
from trees grown above different orchard floor management schemes.
Annual clovers, pea/vetch, berseem clover and glyphosate-treated
orchard floors produced the greatest packouts, whereas annual
ryegrass, perennial ryegrass and resident vegetation (weeds) produced
significantly lower packouts.
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