Italian ryegrass control is one of the most significant limitations in wheat production in the U.S. today. Resistance to Herbicide Resistance Action Committee (HRAC)/Weed Science Society of America (WSSA) Groups 1, 2, and 9 in Arkansas have further complicated postemergence control, while residual herbicides still show effective weed control. One problem is the potential of HRAC/WSSA Group 15 herbicides to injure wheat when applied preemergence, indicating the need for a herbicide safener. A series of experiments were conducted in Fayetteville, AR, to evaluate crop tolerance and Italian ryegrass control using a capsule suspension formulation of S-metolachlor in conjunction with fenclorim-treated wheat. Experiments were conducted as a two-factor factorial with S-metolachlor applied at three rates (0.37, 0.74, and 1.12 kg ai ha-1) and a microencapsulated formulation of acetochlor at 1.05 kg ai ha-1, and three rates of a fenclorim seed treatment at 0, 0.5, and 2.0 g ai kg-1 of seed. Separate experiments utilized either a preemergence (PRE) or a delayed-preemergence (DPRE) application timing. In both experiments, S-metolachlor at 0.74 and 1.12 kg ai ha-1 provided 77 to 96% control of Italian ryegrass by preharvest, whereas acetochlor only provided 49 to 72% control. Visible wheat injury from PRE applications ranged from 7 to 49% for all treatments 21 d after treatment (DAT), with a reduction in injury when fenclorim-treated wheat was used for both the 0.74 and 1.12 kg ai ha-1 rate of S-metolachlor. In the DPRE experiments, wheat injury ranged from 5 to 16% 21 DAT with no noticeable safening from the presence of fenclorim at any herbicide rate. The results of these experiments indicate that a DPRE application using a CS formulation of S-metolachlor would be more favorable for producers to mitigate the potential for injury to wheat while providing Italian ryegrass control. Additionally, at the DPRE application timing, fenclorim is unnecessary for S-metolachlor to be safely applied at the rates evaluated.

In recent years, banded leaf sheath blight in maize (Zea mays L.) has become an important disease that seriously affects quality and yield. This paper aims to evaluate the sensitivity of Rhizoctonia solani Kuhn to thifluzamide on maize, to clarify the effect of seed coating using a thifluzamide suspension agent on safety and physiological indicators and to determine the effectiveness of control of banded leaf sheath blight in the field. In this study, the thifluzamide sensitivity of 102 strains of R. solani in maize from Shandong was determined using the mycelial growth rate method; the average half-maximal effective concentration value (EC50) was 0.086 ± 0.004 μg/ml and displayed a unimodal frequency distribution, indicating that thifluzamide had strong inhibitory activity on the mycelial growth of R. solani in maize. In an indoor pot test, the root activities under 24 g a.i./100 kg seed were found to increase by 78.01%, compared with the control. Similarly, chlorophyll content increased most significantly at this dose, by 32.3%. Thifluzamide (FS) could significantly increase the per-plot yield. Among the examined dosages, 48 g a.i./100 kg seed had the most significant treatment effect, with the yield rate increasing by 15.7% and 14.1%, respectively, in 2017 and 2018 compared with the control. The field effectiveness against banded leaf sheath blight in maize was highest at the dosage of 48 g a.i./100 kg seed for a seed dressing with thifluzamide (FS). These results indicate that thifluzamide has enormous potential for controlling banded leaf sheath blight in maize.

Field experiments were performed in 2016 and 2017 in Missouri to determine whether interactions exist between PRE herbicides and seed treatments in soybean. The experiments consisted of a randomized complete block design with factorial arrangements of varieties, seed treatments, and herbicides. We selected two genetically similar varieties of soybean, one with known tolerance to PPO-inhibiting herbicides and one with known sensitivity. Each variety of seed received three separate seed treatment mixtures (STMs): (1) STM1, imidacloprid plus prothioconazol+penflufen+metalaxyl plus metalaxyl plus Bacillus subtilis+B. pumilis, (2) STM2, Pasteuria nishizawae plus thiamethoxam plus prothioconazol+penflufen+metalaxyl plus metalaxyl plus B. subtilis+B. pumilis, and (3) STM3, fluopyram plus imidacloprid plus prothioconazol+penflufen+metalaxyl plus metalaxyl plus B. subtilis+B. pumilis. Chlorimuron-ethyl+flumioxazin+pyroxasulfone, chlorimuron-ethyl+flumioxazin+metribuzin, and chlorimuron-ethyl+sulfentrazone were applied PRE to each variety and seed treatment combination at 1× and 2× the labeled use rate. Chlorimuron-ethyl+sulfentrazone treatment at the 2× rate resulted in greater injury of 8% and 14% to the sensitive variety than the tolerant in 2016 and 2017, respectively; this was the highest injury observed from any herbicide treatment in either year. In 2017, chlorimuron-ethyl+sulfentrazone resulted in the greatest height reductions in both varieties, but this reduction was more evident in the sensitive (19%) than in the tolerant (6%) variety. Overall, yield differences between the two varieties were not consistent between years, and for both varieties, the sulfentrazone-containing treatments resulted in the highest yield losses. The results of this research indicate that there is a larger interaction between herbicides and varieties than there is between herbicides and seed treatments, or seed treatments and varieties.

Field bindweed, a member of the Convolvulaceae family, is a problematic perennial weed in cotton fields and orchards in northwest China. The species exhibits strong seed dormancy, causing delayed germination. A clear understanding of the mechanisms involved in alleviating seed dormancy is important for effective plant propagation and successful management of field bindweed. Experiments were conducted to investigate seed germination and radicle growth of field bindweed by breaking seed dormancy using mechanical scarification, sulfuric acid, hot-water scarification, cold stratification, and chemical treatment. Chemical treatments (gibberellic acid or potassium nitrate) had no effect on breaking seed dormancy, whereas mechanical scarification (sandpaper and blade) resulted in 92% to 98% seed germination, indicating that seed dormancy of field bindweed was mainly due to the presence of a hard seed coat. Seeds pretreated with 80% sulfuric acid for 15 to 60 min or 98% sulfuric acid for 15 to 30 min had germination rates above 80%, and soaking seeds in 70 C water for 4 to 16 min or in boiling water for 5 to 20s were effective in breaking seed dormancy but had no effect on the radicle growth of field bindweed. Cold stratification at 5 C for 2 to 8wk partially accelerated seed dormancy release, resulting in 53% to 67% seed germination. Results indicated that field bindweed could potentially form a persistent soil seed bank with physically dormant seed; therefore, strategies for eliminating seed production should be adopted.

Fenoxaprop-P-ethyl, a phenoxy herbicide of the aryloxy–phenoxy–propionic acid group, had a strong control effect when applied POST to weedy rice in this study, with the effective concentrations of 294 μM and 218 μM of herbicide causing 50% inhibition (IC50) in plant height and fresh weight values, respectively. However, fenoxaprop-P-ethyl caused phytotoxicity in cultivated rice. Isoxadifen-ethyl, a widely used herbicide safener in rice, can decrease the phytotoxicity caused by fenoxaprop-P-ethyl. Owing to the extremely similar morphological features and physiological properties of weedy and cultivated rice, it is not practical to spray isoxadifen-ethyl directly on cultivated rice plants to safen them. Applying the safener directly to cultivated rice seeds may be a practical alternative method. To improve the biological activity of isoxadifen-ethyl seed treatments, novel compounds were designed by splicing other groups, including amines, amino acids, and 2- methoxy-5-nitrophenol sodium salt, to the parental structure of isoxadifen-ethyl. Through hydrolysis, acyl chlorination, acyl amination, and esterification, a series of isoxadifen-ethyl derivatives were synthesized and their structures were determined by mass spectrometry and 1H nuclear magnetic resonance spectroscopy. The biological activities of five of the isoxadifen-ethyl derivatives, which possessed recovery effects similar to isoxadifen-ethyl, were able to relieve herbicide phytotoxicity. In pot experiments, isoxadifen-ethyl showed almost no activity as a seed treatment, while three derivative compounds, when used independently as seed treatments, were able to prevent the damage caused by fenoxaprop-P-ethyl. The results will help to develop a new control method for weedy rice, thereby decreasing production costs and increasing farmers’ incomes.

Field experiments were conducted in 1986 and 1987 to evaluate the potential of growth regulators mepiquat chloride and chlormequat chloride as seed treatments to protect cotton from fluometuron injury. Fluometuron at two and three times the recommended use rate reduced cotton stand and height on Taloka and Convent silt loam soils both years. Cotton grown on a Sharkey silty clay soil was not injured by fluometuron. Mepiquat chloride and chlormequat chloride increased cotton stands on a Taloka silt loam soil when averaged over rates and years. In general, fluometuron injury to cotton was not reduced by treating seed with 1000 ppmw concentrations of chlormequat chloride or mepiquat chloride. Chlormequat chloride reduced chlorosis and necrosis of cotton treated with fluometuron, but neither growth regulator eliminated cotton injury or yield reduction caused by fluometuron at two or three times the recommended rates.

Cell cycle activity in dry and germinating untreated and treated (soaked in water and subsequently in fungicide) seeds of two sugarbeet cultivars, collected at commercial harvest time (late mature seeds) and about 2 weeks before this (immature seeds), was investigated by flow cytometry, and by immuno-detection of β-tubulin and the B-subunit of the 11 S globulin. Germination capacity and field emergence were tested. With dry seeds of both cultivars, higher G2 / G1 ratios were observed in the radicle tips of late mature seeds, as compared with those from immature seeds. The late mature seeds contained more partly degraded (soluble) B-subunit of 11 S globulin, typical of germinating or primed sugarbeet seeds. Thus events associated with the onset of germination had occurred in the seed lots collected at commercial harvest time. The cytoskeleton protein β-tubulin was not detectable in dry seeds from either harvest. Western blotting revealed an accumulation of β-tubulin during germination and this was faster in the late mature harvested seeds which was correlated with the onset of DNA replication. Soaking enhanced the rate of cell cycle activation during germination as well as vigour, germination capacity, and field emergence. There was positive correlation between the G2 / G1 ratio and the traits examined in laboratory and field tests. It is concluded that a combined analysis of proteins and cell-cycle-related events can be used in understanding and predicting sugarbeet seed quality.

Introduction.Garcinia kola, a multi-purpose fruit tree, produces fruit, seeds, roots and stem which are extensively used in Nigeria, Ghana and other West African countries for dental care. Cultivation of this fruit tree is limited because of poor seed germination. Our study therefore aimed at improving seed germination properties which will promote cultivation of G. kola by rural farmers. Materials and methods. Seeds taken from a single tree of G. kola were treated with cold water (22 °C), hot water (60 °C) and gibberelic acid (0.5 g × L-1) for various lengths of time. They were then put to incubate in sterilized river sand or a thick transparent polyethylene bag to evaluate the capacities of seed to be germinated under such conditions. In addition, the seed moisture content at harvest was also reduced to various levels before incubation in polyethylene bags to determine the critical moisture rate necessary for seeds to germinate. Results. The seeds incubated in the river sand without any treatment before sowing had an average time of germination of 71.2 d and a total percentage of germination of 28% whereas those incubated in polyethylene bags had an average time of germination of 25.8 d and a total percentage of germination of 62% . The cold water treatment, irrespective of the incubation method, did not significantly affect either the mean germination time or the total germination percentage. However, it significantly reduced the spreading out of the seed germination to 5.4 d. The seed pretreatment with gibberelic acid prolonged at the same time the average time of germination and the spreading out of the germination. The seed water content at harvest (50.4%) allowed the best rate of seed germination and the shortest spreading out of the germination period. Conclusion. The pretreatment of freshly harvested seeds with cold water followed by an incubation in a thick transparent polyethylene bag proved most effective in enhancing the germination of G. kola seeds. This procedure has to be recommended to promote the cultivation of this species.

DDT and BHC were used prior to 1954 as grain protectant but gradually malathion was adopted as prophylactic spray at 50 mg/m2. However, during the continuous usage, doses were enhanced up to 150 mg/m2 to meet the level of effective kill. Toxicity studies on different surfaces, seeds, moisture content level, different insects and stages and emergence of resistance were carried out with respect to malathion and several newer insecticides. DDVP was incorporated in spray schedule at 100 mg/m2. Toxicity data on 17 insecticides, three formulations, persistence on six surfaces and three seeds, tests on 13 insects have been utilized to evolve a strategy for future developments of a prophylactic insecticides. Demerits of switching to new insecticides without broad-based toxicity data have also been advocated. Insects, such as, larva of Trogoderma granarium Everts and adults of Tribolium castaneum (Hbst.), Rhizopertha dominica Fab., Callosobruchus maculatus Fab., Lasioderma serricorne Fab. and Sitophilus oryzae Linn, among beetles and Ephestia cautella (Wlk.) and Corcyra cephalonica Staint from moths were found least susceptible to most of the insecticides. Etrimfos and deltamethrin were adjudged superior for large scale use specially as wettable powder and adjudged suitable to sub-tropical conditions. The paper also provides information on currently used insecticides in India, methods of grain storage at rural and organized level and various constraints faced in the developing countries.

An integrated approach to the management of the sorghum shootfly (to keep its population below economic injury level) has been a major thrust of sorghum research workers during the last one and a half decades. The necessary foundation has been laid by detailed studies on the biology of the pest and a fairly thorough understanding of the effect of different ecological factors on the shootfly population. Based on seasonal incidence studies, sowing immediately after the onset of monsoon has proved to be effective for avoiding shootfly damage.

A large number of high yielding and shootfly-resistant derivatives have been developed by crossing agronomically desirable exotic lines with identified resistant sources. The new hybrids and varieties released recently possess low to moderate levels of resistance.

Parasites and predators affecting different stages of the shootfly have been identified but utilization of these natural enemies for the biological control of the pest is yet to be undertaken.

Carbofuran seed treatment has proved to be highly effective for protecting sorghum from shootfly damage. Some other insecticides have also been found to be promising.

Based on the control methods available at present, an integrated package has been recommended for implementation in traditional sorghum growing areas of the country.