Wis. 
Ariz. 
Ark. 
Calif. 
Calif. 
- 23 - 
The Relation of Leafhoppers_and Aphids to the Transmission 
of Vegetable Crop Viruses. Learn species responsible for dissemi- 
nation of truck crop viruses and their importance in epidemiology 
of diseases under field conditions. Habits, host relations, mi- 
gration, and reducing insect vectors by insecticidal, biological, 
and cultural means will be studied. Lab. and greenhouse studies 
will show basic factors involved in vector-virus-plant relation- 
ships: as acquisition sequence; inoculation, retention, and latent 
periods, and vector feeding habits. 
Ent., Hort., Pl. Path. 725 
H. Biological Control of Insects, Mites, etc. 
Insect Parasites and Predators of Insect Pests of Arizona 
Crops. (1) Learn: identity, distribution, and relative abundance 
of insects belonging to families generally recognized as containing 
species parasitic or predatory on other insects; and where needed 
descriptive, biological, and ecological information is lacking; 
and suggest where future work might be profitably done. (2) Evalu- 
ate effectiveness of the more common species of insect parasites 
and predators as control agents. Make related biological and ecologi- 
cal observations for more detailed work. 
Ent. 404 
Abundance of Corn Earworm in Relation to Hosts, Biological 
Control Agents and Physical Environment. (1) Seek causes of 
fluctuation in field populations of corn earworm in corn and in 
other available hosts. (2) Study effect of climate. (3) Analyze 
the effect of predators, parasites, and diseases and further 
investigate host abundance to seasonal population fluctuations. 
Ent. 450 
The Nature and Properties of Insect Viruses.--Investigate: 
the possibilities of in vitro cultivation of insect viruses, by 
means of tissue and cell culture; phenomenon of virus infection 
sensu stricto and particularly the fate of granulosis and 
polyhedrosis virus after ingestion or intrahoemocoelic inocula- 
tion, in the period preceding the formation of inclusion bodies; 
the chemical and physical properties of insect viruses. 
Biol. Control 1333 
The Nature of Infectious Processes in Insects. To increase 
store of basic and fundamental knowledge relating to cause, 
symptomatology, pathogenesis, pathology, and epizootiology of 
the infectious diseases of insects. 
Biol. Control 1484 Coop. HEW-USPHS 
