Page 6 



BETTER FRUIT 



November, igig 



Does Experimenting with Native Predatory Insects Pay 



By Elwin G. Wood, District Horticultural Inspector, Washington State Department of Agriculture 



71 per cent were alive, while of those 

 libeiiiled alter April 24 only 40 per cent 

 were alive. I'p until the first of April 

 the beetles in the cages stored out of 

 doors appeared to be nearly all alive 

 and in good condition. These observa- 

 tions indicate that outdoor storage 

 would be satisfactory if the beetles 

 were liberated by the first of April. 



The beetles given us by the county 

 agent had been stoi'ed in the same cold 

 storage room with ours and were put 

 up in apple boxes, six pounds in a box. 

 They were liberated about the fourth 

 of May and about 70 per cent of them 

 were alive. 



Ladybird eggs were found on April 8 

 at Blalock. They were undoubtedly 

 laid by beetles that had hibernated 

 under rubbish in the orchard. 



As soon as the beetles were liberated 

 they began to hunt for food and within 

 three days were laying eggs on aphis- 

 infested trees. The first larvse from 

 these eggs was observed on May 21 and 

 most of them were hatched by the first 

 of June. Data on observations made on 

 May 22 and 26 is given in the following 

 table. These counts were made in four 

 prune orchards in different parts of the 

 Blalock tracts. The eggs were counted 

 on each of five trees in each of the 

 orchards and the figures given are the 

 average of the five. Only the eggs that 

 could be seen from the ground were 

 counted and the number would un- 

 doubtedly have been larger if the tops 

 of the trees had also been searched. 



[Editor's Note. — The pxpeiiment of coMccling 

 ladybird booties in the fall and liberatiiiK thcni 

 in the spring to pi*ey on apple tree and other 

 species of aphids has atti'acted a great deal of 

 attention in the Pacifle Northwest, not only 

 from professional entomologists and plant 

 pathologists, but also from practical fruit 

 growers. Throngh its slate department of agri- 

 culture Washington this year conducted quite 

 an extensive expei'iment along this line, and 

 (■.alifornia started this fall to collect these 

 l)ectlcs to conduct a widespread experiment 

 next spring. The professional entomologist in 

 most instances is inclined to view these experi- 

 ments with a skeptical eye and to voice the 

 opinion that the more ellicient way of ei'adi- 

 cating ai)hids is by spraying, although a num- 

 ber of them admit that lieneficial results have 

 apparently been obtained where ladybird 

 beetles have been used. The most definite ilata 

 on this question that has been obtained was 

 secured this yeai- in the district adjacent to 

 ^Valla Walla, Washington, by Mr. Elwin G. 

 Wood, horticultural inspector in that district, 

 which is published in the accompanying arti- 

 cle. In this article Mr. Wood arrives at the 

 conclusion that it does pay to collect and liber- 

 ate these insects to prey on aphids.] 



THE experiment of collecting lady- 

 bird beetles to prey on aphids has 

 been the cause of many inquiiies 

 being made as to the actual results ob- 

 tained and the niethoil used in collect- 

 ing and liberating the beetles. 



In Walla Walla County the ladybird 

 beetles begin colonizing as early as the 

 first of July. This year on the fifth of 

 July they had not begun to colonize in 

 the creek canyons near Walla Walla, 

 but on the eighth of July we found 

 large colonics in the canyon of the east 

 fork of the Walla Walla River in Ore- 

 gon above Milton. By the middle of 

 July very few ladybugs could be found 

 in the orchards near Walla Walla. They 

 continue to collect in the mountain can- 

 yons and by September large colonies 

 may be found in the damp places in the 

 canyons of any of the creeks flowing 

 into the valley. They collect in great 

 masses, crawling over damp rocks and 

 logs, and may be collected any time in 

 September and October. As winter 

 comes on they crawl down into the pine 

 needles at the base of the trees and 

 under rotten logs and stumps. In April 

 of the following spring they emerge 

 from their hiding places and for a few 

 days crawl over the damp rocks and 

 stumps in swarms and then disperse in 

 search of feeding and breeding grounds. 

 Very few dead beetles can be found in 

 the places where they have spent the 

 winter. 



This spring in upper Mill Creek Can- 

 yon colonies of beetles began to emerge 

 from their hiding places and appeared 

 in swarms crawling over rocks and logs 

 on about the 10th of April. They were 

 thickest about April 15, and by the 20th 

 they had all disappeared and no more 

 colonics were observed after that date. 

 This suggests that there are about ten 

 days in the spring of the year that the 

 beetles may be gathered and taken to 

 the orchards where most needed. This, 

 too, would be as early as we liberated 

 the ones we had in storage. 



Collecting and Storing. 



Last fall sixty-eight boxes of beetles 

 were collected and stored by Frank 

 George and H. L. Miller. Of these, fifty 

 boxes were made of apple box lumber 



sawed in two lengthwise, giving a box 

 when made up 10x10x11 inches and 

 screened on two sides. These were 

 filled about one-third full of dry excel- 

 sior and three pounds of ladybugs or 

 DO.OOO beetles were put in each. The 

 rest were beehives screened on the top 

 and bottom. Excelsior and four pounds 

 of beetles were put in thirteen of them 

 and six pounds of beetles put in the 

 other five. This made a total of 232 

 pounds of beetles. This spring the 

 county agent gave us 72 pounds of the 

 beetles he had stored, making a total of 

 304 pounds or 9,120,000 beetles liberated 

 by us this spring. In addition to this 

 the county agent liberated 30 pounds or 

 1,080,000 beetles in alfalfa fields in 

 Walla Walla County. 



The beetles were placed in three kinds 

 of storage and accurate data kept on 

 forty-nine of the cages. Twenty-six of 

 the three-pound cages were put in cold 

 storage at 40 degrees on October 26, six 

 cages were put in a basement cellar or 

 common storage on November 8 and the 

 rest were stored above ground out of 

 doors and protected from the snow and 

 rain. 



From a study of the data obtained we 

 discovered that almost 95 per cent of 

 the beetles in cold storage were alive at 

 the time liberated, and if we count out 

 two cages on which water dripped, 

 causing a high mortality, practically 98 

 per cent of the beetles lived, and the 

 cages taken out on May 2 were in as 

 good condition as those taken out on 



A'ame of Dale 



Owner liberated 



Frank George April 21 



Devine April 25 



Julius Levy April 25 



Obenholtzer April 25 



April 17. Of the beetles in common 

 storage only 76 per cent were alive on 

 April 17. Of the ones stored above 

 ground out of doors an average of half 

 of them were dead when liberated. 

 However, of those liberated on April 17 



1>ale eggs 

 and lart'iv 

 were counted 

 May 22 

 May 26 

 May 26 

 May 26 



Total 

 eggs 

 345 

 449 

 200 

 157 



Total ,Vo. of 

 Total eggs & larvee 

 larvee on single tree 



415 

 150 

 152 



864 

 350 

 309 



Ladybird Beetles Colonizing on the Trunk of 



The trees in these orchards were 

 quite badly infested with aphis. De- 

 vine's were so bad that he had sprayed 

 with Black Leaf 40 a few days before. 

 The other men put off spraying until we 

 could see what the ladybugs would do. 

 So far as I know, Devine was 

 the only man who sprayed 

 for aphis in Walla Walla 

 County this year. On June 

 18 no live aphis could be 

 found on the trees at Levy's 

 that had been quite bad three 

 weeks before, and no lady- 

 bugs or larvae were present. 

 On an apjile tree in the same 

 orchard that had some woolly 

 aphis on, three adult beetles 

 and five egg patches were 

 found. Three larvae were 

 found in the curled leaves of 

 another apple tree that had 

 a few rosy aphis. 



Nowhere in the county did 

 the aphis get bad. At Blalock 

 on July 8 there were aphis 

 on the wafer sprouts in a 

 good many trees and very 

 few ladybugs were present. 

 We brought down twenty 

 pounds from East Walla 

 a Tree. Walla Canyon and liberated 



