title: Photosynthesis inhibition of soybean leaves by insecticides.
abstract: Field grown soybean cv. Williams-82 plants were sprayed with malathion or carbaryl formulations at 30, 60 and 90 days after planting. Net photosynthesis (PN) was measured in the control (water-sprayed) and pesticide-treated plants, 1, 3 and 7 days after treatment, with a LICOR 6200 Portable Photosynthesis System. The pesticide-treated plants showed a significant reduction (24% with malathion and 20% with carbaryl) in PN after the first application. After the 60-day spray treatment PN suppression on day 1 and day 3 after treatment was the same as after the first application; but PN reached the same level as that of the water-sprayed control 7 days after treatment. After the 90-day treatment no change in PN was observed with the pesticide-treated plants compared to the control. These data indicate that malathion and carbaryl formulations may exert a detrimental influence on soybean physiology.
authors.affiliation: Central Food and Feed Laboratory, Agricultural Research Center, Cairo, Egypt.
authors.forename: S
authors.initials: S
authors.lastname: Abdel-Reheem
authors.forename: M H
authors.initials: MH
authors.lastname: Belal
authors.forename: G
authors.initials: G
authors.lastname: Gupta