Trans-2-hexenal: mating stimulant for polyphemus moths.

The volatile compound from oak leaves which stimulates the female polyphemus moth to release her sex pheromone has been isolated and identified as trans-2-hexenal. Although leaves of other food plants contain trans-2-hexenal, they also release masking odors which block the activity of the hexenal.

Electrical generation of natural aerosols from vegetation.

It is suggested that an alternative, or additional, source of the blue haze above heavily forested areas may be the generation of submicrometer-sized wax particles by the action of strong electrical fields at the tips of pine needles and other wax-covered plant surfaces. Exposure of pine needles to high potential gradients results in the production of airborne wax particles with diameters less than 0.6 micrometer.

Diethylamide of thujic acid: a potent repellent of Aedes aegypti.

A series of novel, representatively substituted amides of thujic acid were prepared and screened for insect repellent and attractant potential. In repel-lency tests the N,N-diethylamide was the most potent compound, surpassing the activity of the standard repellents dimethyl phthalate and fencholic acid. In contrast, the N-monoethylamide displayed attractant activity.