Journal of Research in Weed Science
Volume:4 Issue: 4, Dec 2021

Data were obtained from the National Bureau of Statistics (NBS) Abuja in February 2021 on pesticides imports into Nigeria to ascertain costs and quantity of pesticides that were used in agricultural and sundry activities in Nigeria from 2010 to 2020 to make an empirical analysis based on pesticide use in Nigeria, Africa and globally. The annual net weight of pesticides used in Nigeria was 23,412.5 Mt, thus ranking Nigeria as the second largest pesticide user after South Africa. The total quantities of each of pesticide types; herbicides, insecticides, fungicides, soil fumigants and mosquito repellants over the 11years periods were 965,558.98, 188,132.37, 66, 129.62, 67,243.97 and 623.56 metric tons respectively, while the mean annual tonnage of each of the pesticide types for the same periods were 87,778.08, 17,102.9, 6,011.8, 6,113.1 and 56.7 metric tons in that order. The quantities of pesticide types used over the periods represent 74.98 %, 14.61 %, 5.14 %, 5.22 % and 0.5 % herbicides, insecticides, fungicides, soil fumigants and mosquito repellant coils respectively. Nigeria spent about 244 million US Dollars annually on pesticides, out of which 74 %, 16.6 %, 4.7%, 5.0 % and 0.06 % were on herbicides, insecticides, fungicides, soil fumigants and mosquito repellant coils respectively. Therefore, it could be concluded that the essence of pesticide use in Nigeria is in agriculture.

In Brazil, morning glory (Ipomoea purpurea L.) is a prominent weed found with sugarcane, maize, and soybean crops, which harms their mechanized harvesting. Its seeds germinate asynchronously, making their management difficult, and glyphosate-tolerant biotypes are also observed in the country. Neem (Azadirachta indica L.) is a medicinal plant, and farmers have widely used its oil for alternative pest and disease management. In this context, this work aimed to evaluate the effect of neem oil, at different concentrations (85, 65, 45, 25 and 5%), on the germination of morning glory seeds. The experiment was carried out in gerbox, in a completely randomized design, and consisted of the five treatments mentioned and a control (without oil), with four replications, containing 50 seeds each. The data obtained were used to calculate the germination time and index. Based on the analysis of the data obtained, it was observed that neem oil at concentrations of 85, 65 and 45% delayed the germination of I. purpurea seeds by 1.83, 1.28 and 1.42 days, respectively. Regarding the germination index, it was observed that oil concentrations of 85 and 45% significantly reduced germination by less than 5 and 6%, respectively. The present study evidences the antagonistic potential of neem oil in relation to morning glory seeds, so that it can be used in alternative management programs for this invasive plant, delaying and reducing germination. Further studies will be carried out to evaluate the effect on seedlings.

Management of Italian ryegrass is frequently done with tank-mix or sequential applications of herbicides. The aim of this study was to evaluate the interaction of haloxyfop-p-methyl or clethodim with 2,4-D, chlorimuron-ethyl and cloransulam-methyl applied in a tank mix or sequential in the control of Italian ryegrass. The three experiments were performed in a factorial arrangement and a randomized complete block was designed, with four replications. Factor A consisted of the haloxyfop (62.35 g a.i. ha-1), clethodim (108 g a.i. ha-1) and chlorimuron (20 g a.i. ha-1) (Experiment I); haloxyfop, clethodim and cloransulam (39.95g a.i. ha-1) (Experiment II); haloxyfop, clethodim and 2,4-D (1005 g a.e. ha-1) (Experiment III). Factor B consisted of tank-mix or sequential (same day) application. Treatments also included an untreated check and the isolated application of herbicides. Haloxyfop and clethodim alone, clethodim+2,4-D, haloxyfop+cloransulam, haloxyfop+chlorimuron, clethodim+cloransulam, clethodim+chlorimuron controlled Italian ryegrass. However, an antagonistic response of haloxyfop+2,4-D was observed. Based on this study, haloxyfop should not be applied associated with 2,4-D in the control of Italian ryegrass; however, the mixtures of ACCase+chlorimuron, ACCase+cloransulam, and clethodim+2,4-D were efficient in the control of the Italian ryegrass.

Morning glory (Ipomoea purpurea L.) is a significant weed in summer crops in Brazil. Castor bean (Ricinus comunnis L.) is an oleaginous plant of high economic and social importance, and its oil has numerous purposes, including pest and disease control. The objective of this work was to evaluate the effect of castor oil at different concentrations (100, 90, 80, 60, 40, 20, 10 and 5%) on the germination of morning glory seeds. The experiment was carried out in a gerbox containing three sheets of germitest paper, in a completely randomized design, corresponding to the seven treatments mentioned (oil dilutions) and the control (only water), with four replications, containing 50 seeds each. Data were obtained by daily reading, where the germinated seeds of each repetition were noted and used to calculate the index and germination time. Based on the experiment, it can be seen that castor oil at a concentration of 100% led to a greater delay in the germination of morning glory seeds, although it did not differ significantly from the concentrations of 80, 60 and 10. The treatment with oil at 5% and 20% advanced germination, although with no significant difference between the control and the 40% dilution. Regarding germination, the 40% dilution significantly reduced the germination index by 1%. It is concluded that castor oil influences (delays) the germination of morning glory seeds, emphasizing on the 100% treatment, which should be studied regarding its effect on germination and seedling development of this weed.

An experiment entitled "Effect of pre and post emengence herbicides on weed management in Sweet corn (Zea mays saccharata sturt.)" was conducted during the 2019 curriculum at Post Graduate Research Farm, Agronomy Section, College of Agriculture, Dhule. The trial consists of ten treatments that are randomly placed in blocks of three meanings. The results of experiment revealed that the experimental site was infested with broad leaved weeds, grasses and sedges. Amongst broad leaved weeds, Comelina benghalensis was the dominant while in grasses, Cynodon dactylon was most prevalent and sedge weed Cyprus rotundus occurred. From the results, it is concluded that sequential application of pendimethalin 1000 g a.i ha-1 (PE) fb tembotrione 120 g a.i ha-1 (30 DAS)(T6) not only reduced the total weed population, weed dry weight at different crop growth stages and weed index but also increased the weed control efficiency and grain yield and was found at par with pendimethalin 1000 g a.i ha-1 (PE) fb 2,4-D dimethyl amine 1000 g a.i ha-1 (PoE)(T7). The highest net returns of 117368 ha-1 was obtained with the treatment pendimethalin 1000 g a.i ha-1 (PE) fb tembotrione 120 g a.i ha-1 (30 DAS) (T6) and BC ratio of 2.97 was obtained with the treatment pendimethalin 1.00 kg a.i ha-1 (PE) fb 2,4-D dimethyl amine 1.00 kg a.i ha-1 (PoE) (T7) (2.97) followed by the treatment pendimethalin 1000 g a.i ha-1 (PE) fb tembotrione 120 g a.i ha-1 (30 DAS) (T6) (2.92) weed free check (T2) (2.71).