Zwick, R. W. <br/><br/>
Probloompetroleum oil aplications for delaying pear psilla (Homoptera :   Psyllidae) oviposition / 
R. W. Zwick, P.H. Westigard 
 - s.l. :   s.n. 
<br/><br/> Sobretiro de: The Canadian Entomologist, 110 (3), 1978 
<br/><br/><label>LCCN: </label>206200 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Control de plagas <br/>Pera -- plagas<br/>Psylla pyricola