Management of Parasitic and Aquatic weeds

Editor's Notes

• #5: The global food production needs to increase by 70% No horizontal expansion of land
• #7: 1961 – 155.8 million hectare 1990 – 163.46 million hectares 2020 – 155.34 million hectares Per capita arable land: 0.34ha (1961) and 0.12ha (2020)
• #8: Biotic constraints Highest potential yield loss
• #9: SPACE,nutrients(47% N, 42% P, 50% K, 39% Ca and 24% Mg ),light,water Coc-manual, tillage,herbicide,spray Quality-weedsbharvested with crop Weed seeds like wild mustard, mixed with wheat grains or edible mustard cause objectionable odor to the flour and can even prove to be poisonous .fetch lower prices . ALLELOPATHIC ; The phenomenon of one plant having detrimental effect on another through the production of certain chemical compounds is called “allelopathy , wild oat has inhibitory influence on WJEAT , Low quality of livestock-undesirable flavour to milk(Cleome viscosa) ,quality of wool, death of animals(dhatura) 4. INSESCTS AND DISEASE:Weeds host many pathogens and insect pests in off-season which migrate to the crop later and cause severe damage. Weeds like Chenopodium album are the common hosts for beetles and cutworm which later migrate to crops like WHEAT AND MAIZE .(Sweet potato weevil Convolvulus arvensis) Others-flow of irrigation water in hannels, harmful to humans(Dermatitis Parthenium),AQUATUC weeds ,reduce value of land
• #10: Abiotuc and biotic constraints to crop production. Weeds are one to the biotic Hughest pot.yield losses along other pests and pthogens
• #12: Parasitism Parasitic plants/hetrotropic /semi-autotropic
• #13: Holo/partial-no chlorophyll.
• #14: Early stages critical
• #15: Roots are more serious because they grow underground
• #16: Essential part of natural ecosystem
• #17: Abundant nutrients Floating (filamentous algae) and rooted chara(musky smell caco3 contact herbi)
• #19: Beneath water Rooted and floating Max loss
• #20: Shallow waters Semi aquatic/marginal Mostly in waterlogged
• #21: Continuously flowing canals rivers large ponds Rooted floating
• #23: Below level of economic injury Adopting ang methid
• #25: Stopping from entering area ,smal area=better, seed bank exhausted,comp;ete exhaustion isn’t possible Complete elimination, difficult, high dose of chemicals,discouraged, (triazines, diuron) Control rather than manage, after weed problem arises, short term
• #26: Compared to non parasitic weed control Physical-1st step Physical-manual and mechanical power, disrupts germination and plant tissues Cultural-designed to give crop a competitive adv.over weeds Biological –living micro Chemical herbicides are integral part of most weed management plamns
• #27: Animal :avoid grazing
• #29: Due to decrease in orobanche and improved soil status due to enhanced decomposition during solarization 8th week host not available
• #30: Trap-soybean Catch-Sudan grass Intercropping-desmodium, cerealsa and legumes Varieties-icsv 145(sorghum), fallows
• #31: Soybean acts as trap crop
• #32: Phelipanche aegyptiaca(broomrape) Biochar absorb GR-24 which stimulate germination
• #35: The fungus was isolated from these tubercles by plating tissues, taken from the edges of the necrotic areas, on petri dishes containing potato dextrose agar (PDA) Koch postulates mana and O. aegyptiaca in the PEB system O. ramosa and O. cumana were highly sensitive, their mortality 3 days post inoculation reaching 95% and 75%, respectively. By 6 days post-inoculation, all tubercles of these two species had died O. aegyptiaca was only ~40% 3 days after inoculation, and after 9 days it reached 70%. In contrast, the fungus did not attack O. crenata
• #38: g 5m x 5m The data indicated that higher dose of glyphosate at early crop stages (T4 ) sometimes caused localized phytotoxicity Single application of herbicide (T4 ) though provided effective weed control upto 70-75 DAS, but the late emergence of new shoots in the later half of crop growth (Table 1) ultimately caused reduction in seed yield due to increased weed seed bank in the soil Supplementation of second spray of glyphosate @ 25 g/ha at 55-60 DAS (T2 ) not only prolonged the effective period of weed control, but also increased 8.7% seed yield in comparison to T4 treatment (Table 1) The tolerance of plants to glyphosate was mainly attributed to readily degradation of this herbicide to non-toxic metabolites It’s fast absorption by the mustard plant foliage and speedy translocation to the young parasites attached to the host roots, leaves, and meristems, are probably the most likely reasons for inhibiting the synthesis of enzyme 5-enolpyruvy lshikimate-3-phosphate (EPSP) synthase that leads to the production of aromatic amino acids (phenylalanine, tyrosine and tryptophan) and protein synthesis and
• #42: Do not fertilize ponds Grass around ponds Livestock away from water bodies Do not permit runoff from sheds coops
• #44: Coconut fibre(450g/m2)89% Hessian 18oz=1mm83% 14oz==2-3mm73%