-3- 



period of June 3. The first cover spray went on about June ^, In these orchards 

 fruit-spur leaf spots \7cre plentrful, furnishing inoculuni after practically all of 

 the vdnter spores had been discharged from the overvidntered leaves. 



Fruit 'p^^^'jr'^j}} To many groovers. Scab spots on the apples v/ere even more 

 difficult to explij In than leaf infections. It is true that :>uit Scab is far more 

 abundant than the dust and spray programs might indicate. It did not occur as 

 sepal infection during pre-pink or early pink bud stages, but as spots on wliat was 

 tlie inner side of the fruit when pink buds were still unseparated. This year the 

 blossom buds generally were unusually late in separating in the fruit bud cluster,- 

 in fact, in many cases not until after one or more of the buds had opened into 

 bloom. This was particularly true in the earlier or low elevation orchards. This 

 meant that, unless the pink spray was delayed until early bloom, the inner surface 

 of many of the small apples received no protective fungicide until the first dust 

 or spray during bloom. Hence, they Trere open to both primary and secondary 

 infections at the first rain that occurred after the buds split apart. 



Remarks: — based upon orchard observations so far: 



1. It is dangerous to omit fungicidal protection on Scab-susceptible 

 varieties during the early-to-late delayed dormant finit bud stage, especially in a 

 season when ascospore maturity is abnormally early. 



2. It is extremely important to delay the pink spray just as long as possible 

 — even until a few blossoms are open — particularly in a season v/hen the fruit 

 buds are reluctant to separate. 



3. In seasons vdien 2 to 3 infection periods occur during bloom, two supple- 

 mentary protections are likely to be needed between the pink spray and the petal- 

 fall spray, especially if an eradicant fungicide is not used in the calyx spray 

 at the end of an infection period. 



U. An emergency or supplementary dust application during bloom or elsewhere 

 in the schedule is likely to be inadequate for protection against Scab unless applied 

 from both sides of the tree. This is particularly true for an extended vret period 

 such as occurred on May 2li-26 during bloom. 



5. Scab spots on fruit spur leaves, that originated at delayed dormant to 

 pre-pink, can be a dangerous source of secondary infection for both fruits and 

 leaves during bloom and even subsequently. Furthermore, such spots are difficult 

 to burn out vdth eradicant fungicides unless applied at pink or calyx. 



6. Secondary Scab infections this year were most pronounced on the upper 

 sides of leaves in the lower parts of the tree — indicating (2) accumulation of 

 spores as they dripped downward through the trees; (b) the lack of enough protective 

 fungicide and at the right time on the lovrer branches; and (c) the absence of 

 appreciable drip and run-off from semi-concentrate applications of protective 

 fungicides. 



7. There was evidence in more than one orchard v/here semi-concentrates, i^X in 

 particular, were applied with a Speed-Sprayer, that the lower branches of the trees 

 vrere not as well protected as the upper tvro-thirds of the tree. Probably, either 

 not enough material v;as delivered to the lower branches or it was not well distri- 

 buted there — in the absence of little or no drip and run-off. A similar failure 



