50 MISC. PUBLICATION 56S, U. S. DEP'T. OF AGBICTJLTTTBE 



In addition to the damage they cause by actually feeding upon plants, 

 insects often are responsible for spreading plant diseases: directly, by 

 carrying the disease germs from one plant to another, and indirectly by 

 leaving breaks in the protective epidermis of the plant through which 

 fungus spores can enter. For this reason, and as previously discussed, 

 it is sometimes difficult to determine whether a plant ailment is due to 

 fungi or insects, or both. 



Kind of Data Needed 



Aside from the general information (see p. 8), the collector should 

 write down all pertinent facts observed, including the kind and degree 

 of damage being caused and whether the insects were reared or caught 

 wild. The elevation should be indicated, because it often has importance 

 in the study of insects. If the plant being attacked is not a well-known 

 crop plant, the collector will need to prepare a pressed specimen of it 

 for identification. 



The insect specimens will require careful labeling and numbering, 

 to prevent mistakes and confusion, and special attention to the re- 

 lationship between the various immature stages and the adult. 



Suggested Notes To Accompany Specimens 



1-4281 Leaf scale 



On tree (Coll. No. 4281) 



10 km. W. of San Martin de la Cruz, on banks of Rio Suciatetomba, Dept. 



Cundinamarca, Colombia, S. Am. El. 1,000 m. July 7, 1939. 



All plants seen were severely infested; causing decided yellowing of leaves 



but not defoliation. Adults with brownish, waxlike covering which flakes off 



to give a dusty appearance to foliage. 

 1-5342 Root borer (beetle) 



On cult, sugarcane. Fazenda Perez, 4 km. S. of town of Bledo, near Belterra. 



Rio Tapajos, Estado do Para, Brazil. El. 300 m. Dec. 2, 1940. 



Causing death of about 50 plants in an acre field. Both adults and larvae 



found inside the roots, and adults apparently feeding there. Two adults 



reared from pupae. 



Photo 19-2 (showing longitudinal section of root tunneled by the grubs). 



Collecting 



The specialist who names insects nearly always needs the adult form, 

 and frequently he may wish to see the immature stages as well. This 

 being true, the field man, especially if he is in a foreign territory, who 

 wants an insect pest identified, may be obliged to rear larvae or nymphs 

 in order to get the adult stage. 



Insect rearing is not always easily accomplished and may require 

 time and considerable experimentation to meet the requirements of 

 different kinds of insects. Pupae already formed can be kept in any 

 sort of box or bottle which is covered tightly at the top with cheese- 

 cloth. Caterpillars, or other immature stages, can often be reared to 

 maturity by placing them in a suitable container with a supply of their 

 food. Large bottles might serve, although many students use old- 

 fashioned lamp chimneys with the base pushed into a pan or pot of 

 dirt and the top covered with cheesecloth. If the soil is kept moist, the 

 branches of the food plant will remain alive for a longer time. Rearing 

 cages made of screen or glass are sold by many entomological-supply 

 houses. They can be constructed easily by nailing wire screen or mos- 



