stance from which alighting flies cannot escape. 

 Pending further advancement and EPA approval, 

 the sticky will be replaced by a mixture containing 

 pesticide, a fly-feeding stimulant, and a residue 

 extending agent to kill alighting flies. 



(4) Following harvest, removal of dropped 

 apples from the orchard floor to preclude buildup of 

 wi thin-orchard populations of codling moths, lesser 

 appleworms, and apple maggot flies that could de- 

 velop to maturity on infested dropped apples. In 

 addition, on blocks of mature trees we will employ 

 root pruning following bloom using a sharpened 

 subsoiling blade mounted on a tool bar to promote 

 earlier reddening of apples and possibly delayed rip- 

 ening, thereby reducing the probability of prema- 

 ture fruit drop (in the absence of Alar) and succeed- 

 ing buildup of codling moths, leafrollers, and apple 

 maggot flies in dropped fruit. 



(5) A biological control approach to manage- 

 ment of aphids and summer generations of leaf- 

 rollers, leafminers, and leafhoppers by permitting 

 buildup of natural enemies of these pests in an 

 orchard environment free of insecticides after early 

 June. 



B. Mites: 



(1) Application of oil (safe on beneficial organ- 

 isms) in April to control overwintering red mite eggs. 

 No further application of miticide. 



(2) Sowing seeds of 4 species of broadleaf plants 

 (clover, plantain, white cockle, and nightshade) to 

 establish a groundcover that will harbor two-spotted 

 mites. Predatory Amblyseius fallacis mites (raised 

 from a strain that is resistant to insecticides used 

 from April to June and purchased from BIOKON, 

 Inc.) will be released in the groundcover in June, 

 where they will be allowed to build on two-spotted 

 mites as prey and then move up into the apple trees 

 to provide effective biological control of European 

 red and two-spotted mites. To prepare for sowing 

 seeds of broadleaf weeds in September, herbicide 

 will be applied in May the length of each tree row in 

 2 bands, each extending from the tree trunks out- 

 ward to 2 meters. The seeds will be sown into these 

 bands after the herbicide-treated sod has been 

 lightly cultivated by a side-mounted weed badger. 



C. Diseases: 



(1) Use of a flail mower to chop fallen apple 

 leaves in November in combination with application 

 of urea sprays to fallen leaves to enhance leaf litter 

 decay and reduce the substrate necessary for over- 



wintering Venturia ascospores to develop and infect 

 trees in the following spring. Leaves may also be 

 chopped in the spring, thereby further disrupting 

 ascospore maturation. These activities also hold 

 promise of reducing numbers of leafminer pupae 

 overwintering in fallen leaves, thereby providing 

 multiple benefit from integrating disease and insect 

 control tactics. 



(2) Assess potential ascospore dose (PAD) in 

 autumn and spring to permit tailoring the timing of 

 the first needed fungicide treatment against apple 

 scab the following spring according to PAD level. 

 Ascospore maturity in 4 geographic regions will also 

 be evaluated in the spring, using microscopic exami- 

 nation of squash mounts, to guide adjustments in 

 making the first fungicide application. 



(3) On-site monitoring of temperature, leaf 

 wetness and humidity conditions in each block to 

 permit precise determination of apple scab infection 

 and fine adjustment of needed fungicide sprays 

 following the first scab treatment. The materials 

 used against primary-season (i.e. ascospore-initi- 

 ated) scab infections will be principally demethyla- 

 tion-inhibiting (DM3) fungicides at rates which will 

 control scab at 10- to 12-day intervals following the 

 initial application. Using this strategy, fungicide 

 use is minimized in terms of both numbers of appli- 

 cations and amounts of fungicide per acre, as com- 

 pared to other fungicide strategies. Secondary scab, 

 if it develops, will be managed using fungicides 

 which are not destructive to predatory mites. 



(4) Summer pruning of all trees in July and 

 early August to open the tree canopy, thereby alter- 

 ing the microclimate within the canopy and thus 

 reducing infection by sooty blotch and fly speck, and 

 perhaps some other summer diseases. This practice 

 will promote earlier and more extensive fruit colora- 

 tion, and provide integration of a disease, a horticul- 

 tural, and an insect management practice by allow- 

 ing earlier harvest and reduced chance of fruit drop 

 (as mentioned, populations of apple maggot and 

 some other insects can build from dropped fruit). 



D. Weeds: 



Mowing once per month from May to October be- 

 neath the tree canopy as well as in the alleyways 

 between trees. Blade height will be adjusted to 

 permit maintenance of about 15 cm of growth of 

 broadleaf plants that support mite predators be- 

 neath the canopy. Mowing on this schedule will 

 lower the humidity in the understory, and may 

 thereby reduce sooty blotch and fly speck infections. 

 Mowing in October will deter mice from invading. 



14 



Fruit Notes, Spring, 1991 



