| Fluorochloridone is one of Pyrrolidinones herbicides, inhibited phytoene desaturase (PDS) of plants. In this study, we use greenhouse pot study, petri dish method, hydroponics and combined with field trial to evaluate crop safety, herbicide controlling spectrum, selective index between garlic and weeds, crop safety of succession crop, toxicity test of Scendesmus obliquus and the joint effect of fluorochloridone tan-mixed with pendimethalin. The results could be summarized as follows:1. The results of greenhouse pot study of crop safety indicated that fluorochloridone was not safe to several crops. Fluorochloridone was safe to Allium sativum L., Helianthus annuus L., Solarium tuberosum L., Coriandrum sativum L. and Daucus carota L. when pre-emergence-applied (PRE-applied) at rate of500g a.i. ha-1, when increasing the rate up to1000g a.i. ha-1, only Allium sativum L. and Helianthus annuus L. were not injured. Brassica Chinensis L., Brassica campestris L. and Raphanus sativus L. were very sensitive to fluorochloridone. Plants of these crops were all whiting and necrosis when treated with fluorochloridone at rates of500and1000g a.i. ha-1for pre-emergence and post-emergence (POST) application. At the trial rates, when PRE-applied, Oryza sativa L., Sorghum bicolor (L.) Moench, Vigna radiate (L.) and Allium fistulosum L. were all whiting and necrosis too.2. The herbicide controlling spectrum of fluorochloridone showed that fluorochloridone had high efficacy against many grass and dicot weeds when PRE-applied. The efficacies of fluorochloridone were above90%against20of35trial weeds at the rate of125g a.i. ha-1when PRE-applied, when double the dose, the number increased to25. But fluorochloridone has no efficacy to dicot weeds like Cassia tora L. and Ipomoea nil (L.) or grass weeds like Aegilops triuncialis L. and Lolium perenne L. ssp. multiflorum (Lam.) Husnot. Though POST application of fluorochloridone has some control affect on trial weeds, it could not offer satisfactory efficacies against most weeds. But90%of Capsella bursa-pastoris (L.) Medik., Myosoton aquaticum (L.) Moench and Chenopodium ficifolium Sm. while above80%of Arenaria serpyllifolia L. and Descurainia sophia (L.) Webb. exPrantl were controlled with POST application of fluorochloridone. 3. Based on the result mentioned in crop safety experiment, dose-response study was done to determine selective index of PRE or POST application between Allium sativum L. and weeds. The trial weeds were Capsella bursa-pastoris (L.) Medik., Descurainia sophia (L.) Webb. exPrantl, Alopecurus japonicus Steud., Lithospermum arvense L., Galium aparine L. and Avena fatua L. The result indicated that sensitive index between Allium sativum L. and six weeds were all above2with PRE application at the trial rates, especially for Capsella bursa-pastoris (L.) Medik. and Descurainia sophia (L.) Webb, ex Prantl, sensitive index of which reach up to102and27.9. However, sensitive index between Allium sativum L. and six weeds were all below2. In conclusion, fluorochloridone was recommoned to use as a PRE application herbicide due to its higher safety for Allium sativum L. and better control efficacy against weeds when PRE-applied.4. The result of effect of fluorochloridone on successive crop showed that, among Triticum aestivum L., Zea mays L., Cucumis sativus L., Raphanus sativus L. and Brassica campestris L., shoot and root of Zea mays L. were less inhibited than other crops’,50%inhibition concentration (IC50) were206.26and224.47mg L-1, respectively while those of Brassica Chinensis L. were the most sensitive to fluorochloridone, IC50were14.29and7.02mg L-1, respectively.5. Fluorochloridone has high efficacy against dicot weeds such as Capsella bursa-pastoris (L.) Medik. and Descurainia sophia (L.) Webb, ex Prantl while pendimethalin, an regular herbicide using for weed control in Allium sativum L.,was not capable of controlling some dicot weeds. Weed spectrum of fluorochloridone and pendimethalin has some complementary. In the study of the joint effect of fluorochloridone tan-mixed with pendimethalin, we test the combination joint effect on Bromus japonicus Thunb. ex Murr., Alopecurus geniculatus L., Capsella bursa-pastoris (L.) Medik. and Descurainia Sophia (L.) Webb, ex Prantl. The results illustrated that when fiuorochloridone combined with pendimethalin with the ratio of7.5～30:25～100, the combination had an additional effect against Bromus japonicus Thunb. ex Murr.; with the ratio of7.5-30:12.5～50, the combination had an additional effect against Alopecurus geniculatus L.; with the ratio of3.25～15:25～100, the combination had an additional or synergistic effect against Capsella bursa-pastoris (L.) Medik.; with the ratio of3.25～15:100～400, the combination had an additional effect against Descurainia sophia (L.) Webb. ex Prantl.. No antagonistic effect was observed in the study indicated the two herbicides can be tank-mixed.6. The results of field trial showed that efficacy of fluorochloridone tank-mixed with pendimethalin or achetochlor had efficacies above95%against Myosoton aquaticum (L.) Moench, Capsella bursa-pastoris (L.) Medik and Eleusine indica (L.) Gaertn.. However, control efficacies against Capsella bursa-pastoris (L.) Medik and Eleusine indica (L.) Gaertn. were below90%when treated with only pendimethalin or achetochlor, respectively. In the crop injury investigation, The first leave of Allium sativum L.plants were injuried at different levels when treated with fluorochloridone and its combinations21d after treatment. But the other leaves were not injured.150d after treatment, the injury symptom was disappear, which show that fluorochloridone has no obviously effect on the growth of Allium sativum L. |
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