Prevalence and Distribution of Weed Flora in Some Major Sugarcane Growing Areas of Southern Guinea Savanna, Nigeria

Weed population survey was undertaken to determine prevalence and distribution of weeds, and asses weed flora shift in major sugarcane growing areas in Southern guinea savanna of Nigeria. The selected areas surveyed are namely Badeggi, Sulti, and Isenyi. The Sugarcane fields were assessed using 1.0 m x 1.0 m quadrat placed randomly at vegetative stage. Weed seedlings in each quadrat were clipped at the soil level and identified according to standards. Result revealed that a total of 38 weed species were recorded. Graminaea and compositae were most abundant and diversified families based on the number of species recorded. Individual weed species shows variation in their abundance, dominance and frequency. The most frequent weed species in the Sugarcane fields irrespective of the soil, climate and crop varieties were Hyptis suaveolens, Paspalum scrobiculata, Kyllinga squamulata, Dactylactenum aegypium and Cynadon dactylon and were considered as the most important species in the surveyed areas. From Similarity indices, variations were observed between locations. Accordingly, areas having similarity indices more than 60 % indicate similarities in weed community. Thus, when devising a weed control strategies same control option should be considered for the location that have similar weed flora and vise-versa.

Weed infestation monitoring in vineyards in the South Sakar region of Bulgaria

The weed infestation monitoring was conducted in 2019 and 2020. The purpose was to document the weed flora in a large part of the wine vineyard plots in the cadastral area of the Kolarovo, Ovcharovo, Dositeevo, Balgarin and Izvorovo villages within the administrative territory of the Harmanli municipality and the micro-climatic region of South Sakar. The established weed species composition was represented by 38 weed species belonging to 18 botanical families in ratio 81.58% to 18.42% monocarpous to polycarpous species classified in a total of nine biological groups.

Sole and Sequential Application of Herbicide and Straw Mulch on Weed Growth and Productivity of Direct Seeded Rainfed Rice (Oryza Sativa L.)

The sole and sequential application of herbicide and straw mulch on weed growth and productivity of rainfed direct seeded rice, were studied with 12 treatments during kharif 2019. Results showed that the application of oxadiargyl fb rice straw mulch @ 6 t/ha registered significantly the lowest weed density and dry weight at 60 DAS; however, it was statistically at par with oxadiargyl fb hand weeding. Weed free check produced the highest grain yield (3.05 t/ha) which was at par with the sequential application of oxadiargyl fb rice straw mulch @ 6 t/ha (2.99 t/ha) and oxadiargyl fb rice hand weeding (2.90 t/ha). Application of oxadiargyl fb rice straw mulch @ 6 t/ha fetched the maximum net return of Rs. 17528/- per ha and return per rupee invested of 1.52. Application of oxadiargyl fb rice straw mulch @ 6 t/ha could be recommended for managing complex weed flora, higher productivity and greater profit in rainfed direct seeded rice cultivation. Bangladesh J. Bot. 50(3): 671-677, 2021 (September)

Influence of Pre and Post Emergence Herbicides on Weed Dynamics, WCE and Yield of Pigeon Pea under Rainfed Conditions

A field experiment was conducted at ICAR-KVK, Kalaburgi, during Kharif seasons of 2018-19 and 2019-20 to adjudge the efficacy of pre and post emergence herbicides against diverse weed flora in pigeonpea ecosystem. The experiment was laid out in RCBD with 11 treatments comprising of different pre-emergent herbicides viz., Pendimethalin, Pendimethalin 30 EC + Imazethapyr 2 EC and post-emergence premix product herbicides such as Imazamox 35 WG + Imazethapyr 35 WG, Propaquizafop 2.5% + Imazethapyr 3.75%w/w ME and their different dosages with cultural methods were compared with weed free check and weedy check treatments. Among the different pre and post emeregent herbicides tested against different weed flora, post emergent application of Propaquizafop 2.5% + Imazethapyr 3.75% w/w ME @ 2000 ml ha-1 at 20-25 days recorded significantly lower weed density, weed dry weight, highest weed control efficiency (91.36%) and lowest weed index (8.78%) and higher grain yield (1209 kg ha-1 ), net returns (` 43,036 ha-1) and benefit cost ratio (2.35) followed by Propaquizafop 2.5% + Imazethapyr 3.75% w/w ME @ 1500 ml ha-1 at 20-25 DAS, Imazamox 35 WG + Imazethapyr 35 WG at 100 g ha-1 at 20-25 DAS and HW at 20 and IC 40 and 60 DAS.

Weed Flora Dynamics in Maize (Zea mays L.) Field as Influenced by Cover Crop Types and Planting Densities at Jalingo, Northeast, Nigeria

Aim: Competition from weeds is an obstacle to profitable maize production. Knowledge of weed species limiting productivity is essential for sustainable management. A two years field experiment was conducted to evaluate the effect of a leguminous cover crop, akidi (Vigna unquiculata sub-sp sequipedalis) and two non-leguminous cover crops (melon and sweet potato) planted at three densities on weed flora composition and shift in maize at Jalingo, North-eastern Nigeria. Study Design: There were 11 treatments replicated three times in a randomized complete block design. Methodology: Low, moderate and high densities (20,000, 30,000 and 40,000 stands/ha respectively) of Akidi, Melon and Sweet potato (A1, A2, A3, M1, M2, M3, S1, S2, S3) with weeded (C1) and unweeded (C2) checks constituted the treatments laid out in a randomized complete block design replicated three times. Weed flora abundance, percentage density, percentage frequency, frequency index and percentage contributions were determined from a 50cm x 50cm quadrat thrown twice per plot at various phases of maize growth. Results: Thirteen weed families made up of 11 broad leaves, one grass and one sedge were identified. The abundance was in the order Broad leaf > Grass > Sedges. The most abundant weed species were: Imperata cylindrica L (3.8), Mucuna utilis (3.0), Oldenlandia herbacea L. (2.6) Sida acuta Burm F, Tridax procumbens L. (2.5 each), Leucas martinicensis, Pennisetum pedicellatum (2.3 each). Commelina benghalensis, Cyperus difformis (3.5), Digitaria horizontalis, Fimbristylis littoralis (2.8 each). The influence of selected cover crops on individual weed percentage the contribution shows: Commelina benghalensis ( C2<C1 < M <S< A), Euphorbia hyssopifolia (C2<M/S < A<C1), Euphorbia heterophylla (M<S<A), Leucasmartinicensis (C1<C2<M<A<S), Mucunautilis (S<M<C1<C2<A) and Sida acuta (M<S<A<C2<C1) while grassy weeds, Imperata cylindrical (A<C2<S<M), Pennisetum pedicellatum (A<C2), Digitaria horizontalis (C1/ C2< A < M <S), Kyllinga squamulata (M/S <C2<A <C1). Commelina spp. increased in status from an accessory (21.2%) to abundance (66.7%) while others increased from rare to accessory (from 0.0 to 20-40%). Conclusion: Akidi was more effective on broad-leaved weeds while melon and sweet potato were more effective on grasses and Commelina benghalensis need to be monitored.