Student at right is using a hand-pumped sprayer. The one at left is holding a glass fruit fly trap in his right hand.
'Fruit trees are sprayed every 10 days and fruit fly traps are inspected weekly. Controlling fruit fly on citrus, spray has sodium fluosilite sugar and water called poison spray' written on back of print.

Probably photographed in the orchards in Horticulture (the row of pines in the background a distinctive previous windbreak planting).