detection and with little fear of predators. Also, 

 previous reports had indicated that crownvetch 

 was unpalatable or toxic to voles; however, 

 evidence of voles feeding on its shoots and leaf 

 stems (but not on leaves) was found in this 

 study. 



On many of the plots treated with 

 glyphosate, a somewhat homogeneous layer of 

 low-growing mosses developed and, although 

 vole activity was still noted, damage was nearly 

 non-existent. Also, only an average of 76% of the 

 so-called "bare soil" plots were devoid of vegeta- 



tive cover. Hardy and persistent "weedy" plants 

 were able to colonize these plots despite herbi- 

 cide treatment, yet a consistent canopy of cover 

 never developed; this apparently prevented or 

 substantially hindered vole use of those plots. 

 Based on the results of their study, Cornell's 

 researchers recommend that growers should 

 consider incorporating a manipulation of 

 groundcovers (i.e. establishing mowed sod, bare 

 soil, or, to a lesser degree, 2.5-yard-wide 

 glyphosate-treated strips) in their integrated 

 approach (e.g., tree guards, rodenticide applica- 

 tion) to minimizing damage caused by voles. 



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Effects of Rootstocks on Apple Ripening 



Wesley R. Autio 



Department of Plant & Soil Sciences, University of Massachusetts 



It is important that factors which can alter 

 the time of fruit ripening be identified. Those 

 factors which are under grower control may be 

 used to expand the harvest season of a single 

 cultivar if the magnitude of the effects is great 

 enough and if the effects are consistent. Al- 

 though, some of these factors are not under the 

 control of the grower, knowledge of the effects 

 should help growers manage their harvest sea- 

 son. Several studies have observed effects of 

 rootstocks on apple ripening; however, because 

 of problems with the studies, it is very difficult 

 to make a clear statement on the nature of these 

 effects. In 1986, 1 began a study of the effects of 

 rootstocks on ripening in the 1980/81 NC-140 

 Cooperative Roots tock Trial at the University of 

 Massachusetts Horticultural Research Center 

 in Belchertown. I reported results from the first 



two years in Fruit Notes 52(2):5-10. Since then, 

 two more years of data have been collected, and 

 a new trial has begun. 



The first trial was with Starkspur Supreme 

 Delicious trees on Ott.3, M.7 EMLA, M.27 

 EMLA, M.9, MAC 9, and OAR 1. They were 

 planted in 1980 and 1981 as part of the NC-140 

 Regional Project. Four fruit were harvested 

 from the periphery of each tree periodically 

 throughout the harvest season in 1986-89. Af- 

 ter harvest, the internal ethylene concentration 

 of each apple was measured. These data were 

 used to determine a date when the average 

 ethylene concentration of the fruit on a tree was 

 greater than 1 ppm, representing the approxi- 

 mate time of the beginning of ripening. Addi- 

 tionally, each year 10- fruit samples were har- 

 vested from each tree for firmness, soluble sol- 



Fruit Notes, Summer, 1991 



