Fipronil seed treatments for the control of chironomid larvae (Diptera: Chironomidae) in aerially-sown rice crops

Environmental fate and toxicology of fipronil

“…5) Fipronil is also highly toxic to midges (Chironomus tepperi), common pests in rice fields, at very low concentrations; the LC 50 and LC 90 are 0.43 mg/L and 1.05 mg/L, respectively. 7) Nearly the same LC 50 for midges was observed in another study. 25) Table 4 summarizes data from several studies addressing the toxicity of fipronil to various insects.…”

The Impact of Herbicides on Benthic Organisms in Flooded Ricefields in Southern Brazil

“…Another factor to consider is the relatively low persistence of the compounds used in this study. All the herbicides except Quinclorac showed lower persistence than found in some studies (USEPA, 1996;Stevens et al, 1998;Mesléard et al, 2005;Mize et al, 2008;. However, Quinclorac was at least 2.5 times more persistent than observed by Reimche et al (2008).…”

Effect of fipronil seed treatments on the germination and early growth of rice

“…Although an apparent trend towards seedling growth inhibition, particularly of the root systems, was apparent nine days after sowing, no treatment effects were signi®cant (P`0.05) and by 25 days after sowing neither signi®cant treatment differences nor apparent trends could be discerned. An apparent phytostimulatory response to ®pronil in rice has been reported in the USA, 10 and in Australia Stevens et al 12 suggested that improved plant growth characteristics found in small plot trials could be a consequence of either a phytostimulatory response to ®pronil or systemic activity. This study has provided no evidence for a phytostimulatory response to ®pronil in rice, and the apparent`en- hanced growth' of ®pronil-treated crops in the ®eld remains unexplained.…”

“…In the USA, ®pronil has been shown to provide effective control of rice water weevil, Lissorhoptrus oryzophilus Kuschel, 8±11 whilst in Australia ®pronil is an effective seed treatment for the control of chironomid midge larvae, including those of the rice bloodworm, Chironomus tepperi Skuse. 12 Applying ®pronil to germinated seed prior to sowing at rates as low as 12.5 g AI ha À1 is an effective technique for chironomid control, 12 whilst seed treatments have also been shown to be effective for controlling rice water weevil. 9,10 Rice et al, 10 in a study on the ef®cacy of ®pronil for the control of L.oryzophilus, found signi®cant increases in plant height in ®pronil-treated ®eld plots, and suggested that ®pronil may have a stimulatory effect on plant growth.…”

“…9,10 Rice et al, 10 in a study on the ef®cacy of ®pronil for the control of L.oryzophilus, found signi®cant increases in plant height in ®pronil-treated ®eld plots, and suggested that ®pronil may have a stimulatory effect on plant growth. Stevens et al 12 found ®pronil to be a superior seed treatment to malathion for chironomid control, and reported better establishment, increased shoot lengths, and better root system dry weights in ®eld plots. The residual control provided by the ®pronil treatments, whilst superior to malathion, did not appear to explain these factors adequately, leading to the conclusion that ®pronil may stimulate plant growth, or alternatively have a systemic effect.…”