s o: IE FEST CO>;mOL PROBIEMS in T\JGOSlAVlk 



In some respects this countiy is sspecially favorable for the research fcnto- 

 mologisto A relatively long, dry summer brings many insect problems and seme good 

 work is being done by research 7\rorkers on life histories and methods of control. 

 But equipment arid materials for a good spray program are quite generally lacking. 

 To mention a few of the more troublesome fruit insects, (1) there are 3 broods of ] 

 codling moth in some parte of the country arjd frequently $0% of the harvested crop 

 shows the characteristic blemishes, (2) San Jose scale, introduced in the late ' 

 Thirties, is causing widespread damage and is interfering with apple exports, (3) the 

 apple blossom weevil destroys a large percentage of the blossom buds in unjarotected 

 orchards, (k) a cherry maggot (similar to the two species four^ in the U.S.) infests 

 the later ripening varieties, (5) a root borer causes the loss of many fruit trees, 

 (6) aphids responsible for the spread of certain virus diseases of stone fruits are 

 a constant menace* 



Apple trees in some areas bloom in April, and Delicious apples may be found 

 in prime eating condition en the trees in late October, Certain varieties of sweet 

 cherries ripen in lata May« These observations suggest a long growing season Avith 

 many hours of sunshine, a situation favorable for insect development. Under these 

 climatic conditions, control of codling moth would require at least 3 thorough, well 

 timed sprays of an effective material, such as DDT. But the DDT manufactured in 

 this country contains only a low peroentage of the essential ingredient and thus far 

 has not been applied very generally for codling i,iOth control. Lead arsenate, with 

 seldom more than 2 applications, is the more common insecticide. One can easily visu- 

 alize what would happen to the codling moth problem if 50 or 1$% Vfettable DDT were 

 widely available along with suitable spraying equipment. Power sprayers are conspi- 

 cuous by their absence. Even some of the Fruit Institutes where experimental work 

 is ur^er way, must get along with a power sprayer of such lov^ capacity that tvi,ro men 

 can spray no more than ^0 trees in a 10-hour day. 



Several gallons of "Superior" oil were brought over from the U.S. for demon- 

 stration purposes in San Jose scale control. In one of these tests at an experiment 

 station, a bucket type pump was actually used for applying this material. The re- 

 sults were very encouraging, vfith more than 9B% control compared with about 92% with 

 the material commonly applied. Along one of the highways, where 20 years ago apple 

 trees had been planted for a distance of ^0 kilometers, many of the trees are severely 

 infested by San Jose scale. Lower elevation orchards seem to suffer more than others 

 because of more favorable weather conditions which influence the number of scale inr- 

 sects, 



A few years ago the bud moth, a minor insect pest in New England, 'Vv'as intro- 

 duced into the country in the absence of its natural enemies or parasites, causing 

 severe defoliation. A laboratory has been set up to develop suitable control meas- 

 ures, including the breeding of parasites „ 



Neither apple scab nor brown rot cause severe damage, partly because of a 

 drier climate and partly because most of the varieties are soine-v*at resistant. The 

 Budimka variety of apple, commonly grown in Serbia, shows little scab even though 

 no fungicidal applications are mado. In vineyards, however, the situation is quite 

 different. Fungus diecwitas are prevalent and copper fungicides are used liberally. 

 In fact, about 80?^ of tha pesticide materials used on Yugoslavian farms is used in 

 vineyards, leaving relatively little to control the insects and diseases of tree 

 fruits . 



Speakinp of "pests',' a large species of rabbit causes much damago to young 



