Page 22 



BETTER FRUIT 



February 



Figure 8— PICKED FRUIT FROM PLAT 3, SPRAYED THREE TIMES WITH 



LEAD ARSENATE 



Apples in large pile free from curculio crescents or codling moth worm holes, 97.4 per 

 cent; apples in small pile damaged by curculio, 2.4 per cent; six apples on box to right 

 damaged by codling moth, i%oo of 1 per cent. 



bearing upon the times of sprays, as will 

 be seen later. 



A few apples were found with worms 

 escaped by June 11, and larvae preparing 

 to pupate were first caught under burlap 

 bands on trunks June 16. From this 

 date forward almost up to the time the 

 apples were picked in October, larvae 

 continued beneath the bands. Before all 

 the larvae of the first generation had left 

 the apples there were some of the earli- 

 est maturing of the second generation 

 worms fully grown and leaving the fruit, 

 thus bringing about an ^jverlapping of 

 generations difficult to separate. 



The first moth of the second genera- 

 tion was secured on June 29, and a num- 

 ber of others were secured during the 

 first week of July. Early in July the 

 first of the second generation eggs were 

 to be found, though the maximum num- 

 ber did not appear for some weeks 

 later. Moths were reared from cages, 

 kept at approximately outdoor temper- 

 ature, as late as September 4, and there 

 is little doubt that moths were present 

 in the orchard at even a later date, for 

 when the Ingram apples in the check 

 block of the experiment were picked 

 the first week in October, there were a 

 few very small, sluggish larvae of cod- 

 ling moth to be found in the fruit, 

 retarded in their development by the 

 cold autumn nights. Indeed, on Octo- 

 ber 7th, while the apples were being 

 examined, what seemed to be a single 

 freshly deposited codling moth egg was 

 found attached to an apple. This speci- 

 men was probably one of a third genera- 

 tion of the insect. For the most of the 

 state there seem to be but two annual 

 generations as established by Dr. Riley 

 in careful studies conducted by him forty 

 years ago. 



Everyone knows the "apple worm" 

 and its work, the "wormy apple." Unlike 

 the curculio, which damages the fruit 

 both as adult beetle and as a larva, the 

 damage from codling moth is done only 

 by the larva. The extent of damage 

 may vary with the stage of the apple's 

 growth when the larva entered, with the 

 variety infested and with various con- 

 ditions. 



By the time the larva has completed 

 its development a large cavity has usu- 

 ally been eaten out about the core, with 

 channels extending through the flesh 

 leading to the surface. Apples wormy 



from the side are damaged more notice- 

 ably than those wormy only at the calyx 

 end, and since the worms that enter 

 later are more likely to be those boring 

 in from the side, the damage upon the 

 fruit, besides being more abundant later, 

 is also proportionately more in evidence. 

 Although the appearance of apples with 

 calyx worm holes is not so seriously 

 impaired at first, they invariably decay 

 when kept in storage. In fact no apple 

 containing an open worm hole extend- 

 ing into the apple from any position 

 should be packed with first class fruit. 

 Such blemishes permit the entrance of 

 the spores of fungi which are responsi- 

 ble for rot, which as a secondary loss 

 outranks even the original damage from 

 the insect. The larvae, when small, 

 often eat small bits from the apple skin 

 while starting to enter the fruit. These 

 are to be found upon unspraj'^ed fruit, 

 though also abundant upon sprayed 

 apples where the minute worms have 

 presumably been destroyed when they 

 attempt to enter. These small blem- 



ishes, sometimes called "specks," upon 

 the apple very closely resemble the 

 healed-over food punctures or "stings" 

 made by the curculio, and as shown by 

 experiment do not perceptibly injure the 

 keeping quality of apples when they do 

 not extend deeper than the skin and 

 when healed or calloused over. These 

 codling moth "specks" on Ben Davis 

 also sometimes grow into the charac- 

 teristic "horns" mentioned as some- 

 times following the curculio punctures. 

 Apples with specks from codling moth 

 are damaged slightly in appearance, but 

 a limited number of specks when small 

 are usually permitted in first class fruit. 

 They cannot be entirely prevented, even 

 by spraying. These specks, however, 

 in many cases without the arsenical 

 spray, would have been the much more 

 damaging worm holes. 



Some of the so-called "June drop" is 

 also due to the falling of apples dam- 

 aged by codling moth, though in Mis- 

 souri the curculio shares as a cause. 

 Due to the two insects in badly infested 

 orchards the majority of the fruit is 

 brought to the ground as green or pre- 

 maturely ripened windfalls. 



The total damage to the fruit crop 

 from codling moth in the United States 

 has been estimated by Dr. Howard, of 

 the Department of Agriculture, at $12,- 

 000,000 each year. The tax of this insect 

 upon apple growers in Missouri in a 

 single year when a full crop is borne 

 runs into the millions of dollars — a drain 

 which with proper treatment could be 

 largely prevented. 



One of the main objects of the spray- 

 ing experiment conducted was to deter- 

 mine the dates of spraying most suitable 

 as a combined treatment against cur- 

 culio and codling moth. Many ento- 

 mologists have shown by experiment 

 how it is possible to proceed in con- 



