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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #129860
Title: EFFECTS OF COMMON AERIALLY-APPLIED RICE HERBICIDES ON THE PLANKTON COMMUNITIES OF AQUACULTURE PONDS.

Author
item PERSCHBACHER, PETER - UAPB
item Ludwig, Gerald

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2002
Publication Date: 10/1/2002
Citation: PERSCHBACHER, P., LUDWIG, G.M. EFFECTS OF COMMON AERIALLY-APPLIED RICE HERBICIDES ON THE PLANKTON COMMUNITIES OF AQUACULTURE PONDS.. AQUACULTURE. 2002. v.214. p.241-246.

Interpretive Summary: Fish ponds are often located adjacent to row crop fields that require aerially applied herbicides that may drift to the ponds. These herbicides are potentially dangerous to aquaculture crops because they could adversely affect plankton in the ponds and thus reduce dissolved oxygen levels or reduce the amount of food available for fry or some adult fish. Rice is one of the crops commonly grown in areas where fish are cultured. This research tested the effects of eleven rice herbicides on water chemistry, primary productivity, and amounts of phytoplankton and zooplankton. The herbicides tested were clomazone, thiobencarb, pendamethalin, propanil-dry, flwable, quinclorac, halosulfuron, bensulfuron methyl, triclopyr, 2- 4-D amine and molinate. None of the herbicides except propanil had an adverse effect on water quality or plankton populations at full, 1/10th, or 1/100th strength recommended application rates. When Propanil was applied at full strength oxygen levels were reduced for two days and when a second application was applied, the full strength and 1/10th strength treatments had increased chlorophyll a and zooplankton concentrations. It appears that most herbicides commonly applied to rice fields have little immediate effect on the pond environment.

Technical Abstract: Eleven, common, aerially-applied herbicides for rice were tested for adverse impacts on pond phytoplankton, zooplankton and water quality. Treatments simulated direct spraying of ponds and amounts of drift at 1/10 and 1/100 direct rates. The study was conducted in 12, 500-l outdoor pool mesocosms. Pond water from an adjacent fish culture pond was used. Water quality measurements were made prior to application and at 24 h and 48 h after application. Commercial compounds tested and direct rates in kg active ingredient ha-1 were clomazone (0.6), thiobencarb (3.4), pendamethalin (1.1), propanil-dry, flowable (4.5), second application propanil-dry, flowable (4.5), quinclorac (0.6), halosulfuron (0.07), bensulfuron methyl (0.07), triclopyr (0.4), 2,4 - D amine (1.7), molinate (5.6). In addition, propanil was evaluated in a second application at the same rates. Except for propanil, the rice herbicides produced no measurable effect on pond plankton or associated water quality. Following the first application at full rate for propanil, morning oxygen levels were reduced below 3 mg/l for 2 d. After a second application of propanil at the full and 1/10th rates there were significant increases in chlorophyll and zooplankton concentrations.