Use of disease resistance varieties, While no absolute resistance has been identified so far, ... Turcicum leaf blight (Northern corn leaf blight) on maize is characterized by long elliptical, grayish green or tan lesions on the leaves measuring 2.5 to 25 cm in length and 4 cm in width. This will clear the surface of corn debris that can be potential sources of disease. To quickly diagnose bacterial blight on leaf: cut a young lesion across and place in a transparent glass container with clear water; after a few minutes, hold the container against light and observe for thick or turbid liquid coming from the cut end of the leaf; Why is it important. Figure 6. 0000041782 00000 n Incidence and distribution Control measure: Chemical method: The leaf blight on maize effectively be controlled by spraying either Captan or zineb. The use of resistant varieties together with preventative measures and natural control will help to . Prevent damage to maize plants during mechanical activities such as weeding, irrigation and fertiliser treatment. 35 0 obj Hosts: Sorghum & Maize. This disease occurs throughout the maize production area in South Africa, periodically causing severe, localised outbreaks. The BASF Clearfield® Plus... Dit vereis ’n aansienlike investering in sonstelsels om koste op jou kragrekening te bespaar. Anthracnose symptoms vary widely depending on numerous factors such as genotype, age of plant and environmental conditions; small oval or elongated water-soaked spots which enlarge up to 15 mm long appear on leaves; lesions develop a tan center and red-brown or orange … 34 0 obj Although both diseases are restricted by leaf veins, the margins of BLS lesions are irregular, whilst those of GLS have a rectangular appearance (Photo 3). BLS of maize 0000031607 00000 n nebraskense. 7. Seed treatment with Metalaxyl at 4 g/kg and foliar spray of Mancozeb 2.5 g/l or Metalaxyl MZ at 2g/l is recommended. Additional sources of inoculum for secondary infection on maize leaves may be bacteria present in irrigation water. sasakii [Thanatephorus sasakii], consists of stripping the lower 2 or 3 leaf sheaths, which arrests upward movement of the pathogen by severing its connection with the succeeding leaf sheath. The bacterium can penetrate maize leaves through natural openings (stomata); therefore, it is likely that the highest infection occurs at midday, during which the leaf stomata are fully opened. ... Synergistic effects of two control measures were observed when one control measure improved the efficacy of the other directly or when one control measure induced host resistance or predisposed the pathogen to increased susceptibility. Turcicum leaf blight of maize in Uttarakhand, attaining epidemic proportions which resulted in 83 per cent yield reduction. >> Sprayed control. Tillage is another thing that will help, which is especially effective as a preventive measure. In dry weather, the disease rarely occurs or does not spread enough to cause significant economic damage. Bacterial whorl and stalk rot of maize are prevalent and damaging in areas with high rainfall and/or irrigation, particularly in poorly drained soils. Incidence and distribution Erwinia chrysanthemi pv. Currently the recommended control measures of the northern leaf blight of maize are the use of relative resistant or tolerant cultivars, Tillage to bury infected residue may also be helpful where erosion is not a problem while, crop rotation is also helpful because the disease tends to increase in continuous cropping and the use of fungicides. Symptoms seen on corn include leaf lesions, discoloration (), and foliar blight. Host plant resistance is considered as most practical, feasible, cheapest and most effective way to control leaf blight diseases be- Daarom is dit belangrik om seker te maak jou sonstelsel... Write CSS OR LESS and hit save. It is possible that BLS can survive on maize stubble and infect maize seedlings (primary infection) when environmental conditions are favourable. Initial symptoms are the colouration of leaf sheaths and stalks at internodes. Infections higher up in the plant can have a negative effect on plumes and thus also negatively affect pollination. The following points can serve as guidelines to reduce the risk of infestations. Among them, maydis leaf blight of maize (MLB) caused by Helminthosporium maydis is an important disease particularly in warmer maize growing areas and causes significant yield losses. ... crop rotation and plowing debris into soil may reduce levels of inoculum in the soil but may not provide control in areas where the disease is prevalent; ... hybrids differ in their susceptibility to the disease and further information is required in order to develop specific control measures. Foliar Spray at first appearance of leaf blight with Mancozeb 75% WP @ 1.5 to 2 kg/l of water followed by 2 to 4 applications at 10 days interval if needed. Disease surveys conducted in infected fields showed that rotting of the whorls had a cut-off effect on leaves. Water and bacteria accumulate in the whorl. 8. To quickly diagnose bacterial blight on leaf: cut a young lesion across and place in a transparent glass container with clear water after a few minutes, hold the container against light and observe for thick or turbid liquid coming from the cut end of the leaf Why is it important Monitoring is also important to control corn leaf blights. Turcicum leaf blight (Northern corn leaf blight) on maize is characterized by long elliptical, grayish green or tan lesions on the leaves measuring 2.5 to 25 cm in length and 4 cm in width. 0000001242 00000 n Holcus spot: Pseudomonas syringae pv. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Environmental conditions that promote the disease are moderate temperatures (18°C - 27°C), moist conditions and long dew periods. Avoid excessive flooding and irrigation of fields, especially during hot hours of the day (32°C to 35°C) and attempt to schedule irrigation times to be restricted to cooler hours. Maize is vulnerable to numerous diseases at various growth stages in the field as well as during storage. Cultural Control and Sanitary Methods Various general recommendations have been made to control C. carbonum and other maize diseases including the destruction of plants, crop rotation, spraying with fungicides or nitrogen and potassium fertilization (Aleksandrov and Primakovskaya, 1980; Smiljakovic, 1975). Maize for NCLB control with sunburn symptoms ( Photo 1 ), which includes both monocots and dicots sporadically environmental. 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