- 7 



f i n i n 

 tracto 

 ing sp 

 the sp 

 i s a V 

 total 

 i s a V 

 very r 

 down t 

 still 

 e f f i c i 

 that w 



g. W 

 r, re 

 ray i 

 rayer 

 ery r 

 time 

 ery r 

 api d 

 abo 

 use t 

 ency 

 e cou 



ith dilute sprays, applied by two men using a sprayer, 

 fill unit and a truck, the time spent in actually apply- 

 s less than 50% of the total time in the orchard. When 



is changed from dilute to 3X or 4X concentrate, there 

 apid increase up to about 75 in the percentage of the 

 spent in actually applying spray. This means that there 

 apid increase in the acreage covered each day and a 

 decrease in costs per acre (about $4.00 for dilute/acre 

 ut $2.80 for 3X if the grower has sufficient acreage to 

 he sprayer for 200 hours each year). The increase in 

 beyond 3X or 4X is slow, and for several years it seemed 

 Id not make much further progress in cost reduction. 



In 1963, Dr. Donald Frear and his coworkers from several states 

 published a bulletin in which they gave data on the rate of disap- 

 pearance of many chemicals from crop plants. These data, and those 

 of many other workers, showed that with many pesticides the spray 

 residue on the plant decreased rapidly within the first few days 

 after application. Thus, such pesticides can logically be consid- 

 ered short-life chemicals not adapted to spray schedules with very 

 long intervals between sprays. 



In 1964, Dr. K.D. Hickey and I published the results of stud- 

 ies in which we found that we obtained good spray coverage and a 

 light chemical deposit on more than 90 per cent of the leaves on 

 pruned apple trees sprayed only from one side with an airblast 

 sprayer traveling at 2 mph and delivering 90,000 cfm air at a vel- 

 ocity of about 125 mph. 



whol e 

 were 

 opera 

 no t b 

 cover 

 tende 

 cal s 

 week , 

 due a 

 in th 

 in th 



ers h 

 chard 

 eral 

 work 

 of wh 

 cial 

 d i 1 u t 

 use 

 and s 

 the s 

 to me 



In 19 

 situ 

 being 

 ting 

 e nee 

 age o 

 d to 

 from 



ri gh 

 t max 

 e use 

 e usu 



This 

 as be 

 s. P 

 objec 

 can b 

 at we 

 orcha 

 e spr 

 f Che 

 pray 

 econd 

 dium- 



65, it was clear that we had reached a point where the 

 ation could be reviewed. The refill unit and its driver 



used only a few minutes of each hour with the sprayer 

 a 3X; if this could be increased to 6X perhaps they would 

 ded at all. If spraying from one side gave reasonable 

 f over 90 per cent of the leaves with chemicals which 

 disappear within a few days, why not apply these chemi- 

 alternate sides of the row at weekly intervals (left one 

 t the next) and attempt to maintain a fresh spray resi- 

 imum effectiveness. This might allow a substantial cut 



of chemical per year as compared to 3X sprays applied 

 al way at the usual intervals. 



idea 

 en u 

 rope 

 ti ve 

 e sc 

 mig 

 rd s 



ay p 

 mica 

 i nju 

 man 

 size 



of alternate row spraying with large airblast spray- 

 nder trial for four years and is in use in many or- 

 rly managed, a program of this type can fulfill sev- 

 s that every fruit grower is interested in. The 

 heduled at a definite time each week. The total cost 

 htcall a mai ntenance- type program in a good commer- 

 hould run in the range of 50 to 65 per cent of the 

 rogram as listed in our Pennsylvania bulletin. The 

 Is per year has been cut substantially; so both residue 

 ry problems have been decreased. The filler unit and 



in the spray crew can be eliminated on many small 

 d farms. 



