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Bean Growing (Part II)Bean growing for grains is considered as an extensive field crop, while green bean is distinctly considered as horticulture.
1. Taxonomy and Origin
- White Spider (Polyphagotarsonemus latus) This pest attacks mainly green peppers, but has occasionally been found in tomato, eggplant, beans and cucumber. The first symptoms are ripple of nerves in the apical buds and leaves, and curvatures in most developed leaves. In more advanced attacks, dwarfism and intense green color of the plants occurs. It is distributed in zones inside the greenhouse, although it disperses quickly in hot and dry periods. Preventive control - Dusting of micronized sulfur Chemical control Active substances: abamectin, paraffin oil, colloidal sulfur, micronized sulfur, wettable sulfur, ground sulfur, sublimed sulfur. - Whitefly (Trialeurodes vaporariorum and Bemisia tabaci) The young parts of the plants are colonized by adults by laying their eggs on the underside of leaves. The first larvae that emerge are mobile. After being fixed on the plant, they pass through three larval stages and one pupal stage. Direct damage (yellowing and weakening of the plants) are caused during larvae and adults feeding by absorbing the sap of the leaves. Indirect damage is due to the proliferation of black moulds produced during feeding. This damage stains and lowers the value of the fruits and hinders the normal development of the plant. Both types of damage become important when the pest population level is high. Preventive control and cultivation techniques - Placement of mesh on the bands of the greenhouse. - Cleaning of weeds and crop residues. - Do not combine different crops in the same greenhouse. - Do not leave the buds at the end of the cycle, as young shoots attract adult whiteflies. - Placement of yellow chromatic traps. Biological control through natural enemies Major parasites of whitefly larvae: - Trialeurodes vaporariorum. Native beneficial insects: Encarsia formosa, Encarsia transvena, Encarsia lutea, Encarsia tricolor, Cyrtopeltis tenuis. Beneficial insects used in release. Encarsia formosa, Eretmocerus californicus. - Bemisia tabaci. Native benefical insects: Eretmocerus mundus, Encarsia transvena, Encarsia lutea, Cyrtopeltis tenuis. Beneficial insects used in release.: Eretmocerus californicus, Eretmocerus sineatis. Chemical control
- Seedcorn maggot (Phorbia platura) This dipterous insect can cause a serious loss in beans for grains during sprouting period, which in some cases, sowing must be repeated. The most serious attack takes place in spring, caused by the first generation larvae, on buried seed or seedling cotyledons before sprouting. The larvae destroy the cotyledons, young stems and young roots before the sprouting, by making galleries on them. Seedcorn maggot attack causes the weakening or even the complete destruction of seedlings. Moreover, infected plant is more susceptible to Fusarium. The most intense attacks occur in environmental conditions with high humidity, low temperature and high content of organic matter in the soil. Preventive control cultivation techniques - Perform seed treatment before sowing, usually through moisturizing technique with insecticide (Diazinon, Fenthion and Lindane) accompanied by a fungicide. - Do the planting when conditions are suitable for rapid germination. - Avoid growing beans in wet terrain with lots of organic matter. - Do skim ploughing before planting in order to dry up the ground. - Aphid (Aphis gossypii and Myzus persicae) They are the most common and abundant aphid species in greenhouses. They exhibit polymorphism, with winged and wingless females of viviparous reproduction. The wingless types of Aphis gossypii have black siphons on their green or yellowish body while Myzus are completely green (sometimes brown or pink). They form colonies and are distributed in clusters that are scattered mainly in spring and autumn by the winged females. Preventive control and cultivation techniques - Placement of mesh on the bands of the greenhouse. - Elimination of weeds and wastes from the previous crop. - Placement of yellow chromatic traps. Biological control through natural enemies - Native predatory species: Aphidoletes aphidimyza. - Native parasitoid species: Aphidius matricariae, Aphidius colemani, Lysiphlebus testaicepes. - Native parasitoid used in release: Aphidius colemani. Chemical control
Thrips (Frankliniella occidentalis) Adults thrips colonize crops by laying their eggs inside the vegetal tissues of leaves, fruits and especially of flowers (they are floriculture), where the highest levels of population of adults and hatched larvae are found in sunsets. Direct damage is caused by larvae and adults feeding, especially on the undersides of the leaves, leaving a silvery appearance in the affected parts which become necrotic later on. These symptoms can be seen in affected fruits (especially in pepper) and in extreme cases on the leaves. The laying of eggs can be observed when they occur in fruits (eggplant, bean and tomato). Indirect damage has the utmost importance due to the transmission of tomato spotted wilt virus (TSWV), which affects pepper, tomato, eggplant and beans. Preventive control and cultivation techniques - Placement of mesh on the bands of the greenhouse. - Cleaning of weeds and crop residues. - Placement of blue chromatic traps. Biological control through natural enemies Native beneficial insects: Amblyseius barkeri, Aeolothrips sp., Orius spp. Chemical control
Leafminers (Liriomyza trifolii, Liriomyza bryoniae, Liriomyza strigata, Liriomyza huidobrensis) Adult females lay their eggs within the tissue of young leaves, where a larva that feeds on the parenchyma begins to develop, causing the typical galleries. The shapes of the galleries are different from one another, but not always distinguishable between species and crops. Once completed the larval development, larvae leave the leaves to pupate in the soil or on other leaves, to subsequently transform them into adults. Preventive control and cultivation techniques - Placement of mesh on the bands of the greenhouse. - Elimination of weeds and crop residues. - In heavy attack, remove and destroy the lower leaves of the plant. - Placement of yellow chromatic traps. Biological control through natural enemies - Native parasitoid species: Diglyphus isaea, Diglyphus minoeus, Diglyphus crassinervis, Chrysonotomyia formosa, Hemiptarsenus zihalisebessi. - Parasitoid species used in release: Diglyphus isaea. Chemical control
- Caterpillars (Spodoptera exigua, Spodoptera litoralis, Heliothis armigera, Heliothis peltigera, Chrysodeisis chalcites, Autographa gamma) The main difference between species in the larval stage is seen in the number of false abdominal legs (5 in Spodoptera and Heliothis and 2 in Autographa Chrysodeixis), or in the way of moving in Chrysodeixis and Autographa by arching their body (camel caterpillars). The presence of silks (long "hairs") on the surface of the body of the larva of Heliothis, or the dark brown coloration especially on the legs and head of the caterpillars Spodoptera litoralis, also differs them from other species. The biology of these species is quite similar, passing through egg stage, 5-6 larval stages and to pupa stage. The eggs are layed on leaves, preferably on the underside, by a large number of species of the genus Spodoptera which do the laying of eggs in groups while other species do it in isolation. Damage is caused by larvae feeding. In Spodoptera and Heliothis, the pupal stage takes place on the ground while Chrysodeixis chalcites and Autographa gamma, takes place on the leaves. The adults are moths with nocturnal and crepuscular habits. The damage can be classified as follows: damage to the vegetation (Spodoptera Chrysodeixis), damage to the fruits (Heliothis and Spodoptera) and damage on the stems (Heliothis and Ostrinia) which they can get at the point of cutting the plant stem. Preventive control and cultivation techniques - Placement of mesh on the bands of the greenhouse. - Elimination of weeds and crop residues. - In the case of heavy attacks, remove and destroy the lower leaves of the plant.. - Placement of pheromone traps and light traps. - To monitor the early stages of crop development, it is during this stage when they can produce irreversible damage. Control biológico mediante enemigos naturales - Indigenous parasites: Apantelles plutellae. - Indigenous pathogens: VPNSe-SP2. - Biological products: Bacillus thuringiensis. Chemical control
- Nematodes (Meloidogyne javanica, M. javanica, M. arenaria and M. incognita) They affect practically all horticultural crops, producing root nodules. They penetrate underground roots. Fertilized females which are filled with eggs, take a globular aspect within the roots. Together with the hypertrophy produced in the tissues of the same roots, the results will be the formation of a sequence of nodules. These damages cause clogging vessels and prevent the absorption of nutrients by the roots that cause lower plant development, chlorosis, dwarfism and the appearance of green-wilt symptoms in the hottest hours of the day. They spread in lines or stands and are easily transmitted by irrigation water, by the farmer footwear, by the tools and by any means of land transportation. Furthermore, nematodes interact with other pathogens, either actively (as vectors of virus) or passively by facilitating the entry of bacteria and fungi through the wounds that they cause Preventive control and cultivation techniques - Use of resistant varieties. - Disinfection of soil in previously infected plots. - Use healthy seedlings. Biological control through natural enemies - Biological products prepared with the fungus Arthrobotrys irregularis. Control by physical methods - Steam sterilization. - Soil solarization, which consists in raising the soil temperature by placing a clear plastic sheet on the floor for at least 30 days. Chemical control - Active substance: Metam Sodium. 7.2. Illnesses - "Ash" or powdery mildew (Sphaerotheca fuliginea) The symptoms are white powdery spots on the leaf surface (upper and lower surface) that can cover the entire leaf vegetative structure. It also affects stems and petioles and even fruit in very severe attacks. Infected leaves and stems become yellowish and dry out. Weeds and other cucurbitaceous crops, as well as crop residues would be the sources of inoculums and the wind is responsible for transporting the spores and spreading the disease. The temperatures range between 10-35°C, with an optimum temperature of 26°C. Preventive control and cultivation techniques - Elimination of weeds and crop residues. - Use healthy seedlings. - Perform treatments to structures. - Use of bean varieties which are partially resistant to the two types of the pathogen. Chemical control - Active substancess: sulfur, azoxystrobin, boscalid, tebuconazole. - Grey mould (Botryotinia fuckeliana, Botrytis cinerea) Parasite that attacks a wide range of plant species, affecting all protected horticultural crops, being able to act both as a parasite and as a saprophyte. In seedling, damping-off occurs while brown lesions are produced in leaves and in flowers. A soft mould occurs in fruits (more or less aqueous, depending on the tissue), in which the grey mycelium of the fungi is observed. The main sources of inoculums are conidia and plant residues that are dispersed by wind, splashing rain, drops of condensation on plastic and irrigation water. The temperature, relative humidity and phenology can separately or jointly affect the development of the disease. The optimum relative humidity ranges around 95% and the optimum temperature is between 17ºC and 23ºC. Infected and detached petals disperse the fungi. Preventive control and cultivation techniques - Elimination of weeds, crop residues and infected plants. - Take special care in time of pruning, making clean cuts and fit flush with the stem. If possible, the pruning is done when the relative humidity is not very high. Apply fungicidal paste. - Control the levels of nitrogen. - Use plastic covers in the greenhouse to absorb ultraviolet light - Use suitable plantation setting that allows aeration. - Proper ventilation and irrigation management. Chemical control - Active substances: boscalida, captan, cyprodinil + fludioxonil, fenhexamide, folpet, iprodione, mancozeb, pyrimethanil, tebuconazole. - White mould or white rot (Sclerotinia sclerotiorum) Polyphagous fungus that attacks most horticultural species. In seedling, damping-off occurs. In plant, it produces a watery soft mould at first (no apparent bad odor) which dries out later, depending on the succulence of the affected tissues, covering a rich white cottony mycelium and the presence of numerous white sclerotia which turn to black later on. The frequent attacks and the sclerotia inside the stem will quickly destroy the plant. The disease starts from the ground sclerotia from previous infections, which germinate in conditions of high relative humidity and mild temperatures, producing a variable number of apothecia. The mature apothecium produces numerous spores, which mainly affect the petals. When they fall on stems, branches or leaves, secondary infections are produced. Preventive control and cultivation techniques - Elimination of weeds, crop residues and infected plants. - Use plastic covers in the greenhouse to absorb ultraviolet light. - Use suitable plantation settings to allow aeration. - Proper management of ventilation and irrigation. - Solarization. Chemical control
- Phytophthora root and crown rot (Phytophthora spp. and Pythium sp.) They cause plant diseases both in seedlings and in transplants of various horticultural crops. If the attack is prior to the plant emergence, sprouting defects can be observed. They cause wilting, desiccations with or without yellowing in the aerial part of the plant. The plant collapses and falls on the substrate. It can also be observed constrictions and rot on the crown while rot and lost root in the roots. The similarity of the symptoms, which can be confused with each other and with other symptoms made by non-parasitic agents, requires the identification of the pathogen in specialized laboratories. The disease usually progresses rapidly and can originate from contaminated peat and substrates, through irrigation water or through windblown loaded with soil particles. Preventive control and cultivation techniques - Healthy seeds and seedlings. - Substrates with health guarantee. - Disinfected trays, tools and structures (bleach, formol, quaternary ammonium), avoiding direct contact with the ground thereof - Use of well fermented manure. - Pathogens free irrigation water. Cover the pond. - Avoid high plantation density. - Avoid flooding. - Solarization. Chemical control - Active substances: captan, folpet, iprodione, pencycuron, pyrimethanil, tebuconazole. - Chalara elegans Symptoms include leaf chlorosis and loss of plant vigor. In the roots, a black root rot is observed. The fungus enters through the wounds caused by the emergence of secondary roots. Chlamydospores are able to persist up to 4-5 years in root tissues and up to 3 years in underground. As a saprophyte, it can live indefinitely. The severity of the disease influences soil pH (there is little incidence in a pH less than 6). High soil humidity is favorable to its development, although it is also able to develop in relatively dry soils. Preventive control and cultivation techniques - Healthy seeds and seedlings. - Substrates with health guarantee. - Avoid ground flooding during planting/transplanting. - Rhizoctonia solani In beans, it produces red cankers on hypocotyl and root rot in seedlings, causing wilting and death of these. In other cases, cankers can be healed and the plant can survive with a consequent reduction in growth and production. Through splattered contaminated soil, it is also observed aerial attacks in beans, characterized by reddish-brown sunken cankers on fruit, stems and leaves. The damage is more important in creeping and outdoors varieties. Infection period ranges from few days to several weeks, depending on the tissue and on the amount of moisture present. Preventive control and cultivation techniques - Healthy seeds and seedlings. - Reduce the time from sowing to emergence (for example by reducing the depth of sowing). - Substrates with health guarantee. - Avoid over-watering and have a good drainage design. - Solarization. - Crop rotation, for it is a very polyphagous soil fungus. - Weed removal. - Avoid making wounds or cuts to the plants, because pathogens can enter through them. - Keep the soil rich in humus, the pathogen prefers dead matter in the soil and little by little loses its ability of attacking living tissue. Chemical control
- Fusarium solani fsp. phaseoli Symptoms consist of root necrosis and dry rot on the upper portion of the taproot and crown, which turns reddish in colour. In the aerial part, decreased plant vigor and production is observed. The lower leaves show chlorosis and desiccation. Fungal development is favored with very compact soils, excess nitrogen fertilizer, low temperatures and excess moisture in the soil. Optimal temperatures for disease development are 15-26ºC. Preventive control and cultivation techniques - Avoid excessive soil compaction. - Avoid excessive nitrogen fertilization. - Avoid planting during low temperatures and with excessive soil humidity. - Solarization. Chemical control - Active substancess: Folpet. - Bean rust (Uromyces phaseoli) This disease is widespread throughout the world. It usually develops in temperatures around 21°C and is manifested by yellowish spots on the upper side of the leaves and brown spots on the undersides. The attack can also affect the pods. This disease is usually more common in the autumn growing season. Chemical control
- Bacterial soft rot (Erwinia carotovora) This illness is caused by Polyphagous bacteria that attack most horticultural species which penetrate through plant wounds and invade medullar tissues and usually causes watery and soft rot that often release a foul smell. Moist and blackish spots appear on the stem. In general, the plant usually dies. It can also produce watery rot in fruits. It has a great saprophytic ability, so it can survive in the soil, in irrigation water and in the roots of weeds. High relative humidity conditions and temperatures between 25 and 35ºC favor the development of this illness. Preventive control and cultivation techniques - Elimination of weeds, crop residues and infected plants. - Avoid pruning wounds. - Proper ventilation and irrigation management. - Disinfect tools with a dilution of 20% bleach. - Avoid excessive nitrogen fertilization. - Choose a suitable setting for planting that enhances good air circulation. Chemical control - Chemical treatments are not very effective once the plant is infected. It is better to use cultivation techniques. - Xanthomonas campestris Bacterial invasion of the leaves through the stomata and plant wounds manifests small moist areas, pale green in colours which take a frail brown appearance and surrounded by a yellow halo as they continue to develop. Frequently, the infection progresses by invading most of the leaflet. In stem, reddish longitudinal stripes appear which have watery aspect during its initial stage in small plants. In pods, small moist and dark green lesions appear at the beginning which can dry up and sink and take a brick red coloration that extends from the center to the edge. In infected seed, wrinkling usually occurs on the cover. From these symptoms, systemic infection can be produced which causes fast withering of seedlings and plants, especially at temperatures of 25-35°C. Sometimes at the stem nodes and in the veins of the leaves, reddish-brown lesions appear. Primary infection usually originates from infected seeds, then it will be scattered by rain and wind, sprinkler irrigation and probably by insects. The severity of the disease is higher during rainfall with high humidity conditions and at temperatures of 28°C. Preventive control and cultivation techniques - Use healthy seeds. - Use of resistant varieties. - Avoid high relative humidity. - Eliminate infected plants. - Do not water by aspersion, in case of seedbeds infections. Chemical control - The applications of copper products slow the development of the disease, but have limited effectiveness if cultivation techniques are not implemented. - Halo blight of beans (Pseudomonas syringae) In leaves, a small, moist and oily angular lesion appear, surrounded by a pale or yellowish green halo. In stalk, sunken lesions can be observed. In fruits, greasy lesions may appear which take a reddish or brownish halo later. If the seed is infected, it may produce systemic infections like chlorosis, roughening, reversible wilting, leaf mosaic and leaf deformation. Sometimes, tiny moist areas appear at the stem nodes which gradually increase until they enclose the stem completely. The first infected areas are caused by infected seeds and weeds, and from them they disperse to other plants through the splashes of rain and from these, they can be extended to the whole plot through windblown particles. Preventive control and cultivation techniques - Use healthy seeds. - Use of resistant varieties. - Avoid excess moisture. - Eliminate weeds. - Eliminate infected plants. Chemical control - Apply treatment in case of illness development with copper, mancozeb o maneb. - Virus
- Bean yellow mosaic virus (BYMV) This virus affects numerous horticultural plants. It is transmitted by the sap, seeds and by aphids in a non-persistent manner (Myzus persicae, Aphis fabae, Acyrthosiphon pisum and Macrosiphum euforbiae). The transmission rate is more important in infected plants before flowering. Symptoms begin with small chlorotic areas that gradually extend, giving the whole plant a chlorotic appearance. Later, surface dents and leaf distortions appear that tend to become more intense as the plant grows. Decreased growth and shortening of apical internodes also take place. The pods may be malformed, curved and may have few seeds. - Bean common mosaic virus (BCMV) It is transmitted by aphids in a non-persistent manner through the seeds and pollens (Myzus persicae, Aphis fabae, Acyrthosiphon pisum and Macrosiphum euforbiae). The sale of infected seeds in the market is a dangerous means of virus dissemination in all areas of bean crops. This virus usually manifests with spots in light-green or dark-green mosaic, accompanied sometimes by a vivid reddish colour. Other symptoms include dark green strips of surrounding nerves, wrinkling of leaf blade, curled down leaves and deformations. If temperatures are very high, some strains of the virus produce dwarfism and root necrosis. Sensitive plants are weakened which cause flower and harvest reductions, both in fresh pods and in grains. Control of virus diseases - Use of resistant cultivars and healthy seeds. - Treatment against aphids. 8. PHYSIOPATHOLOGY - Falling of flower: the flower is the weakest organ of the plant and any deficiencies during its development may cause its falling. The causing factors include: abrupt changes in temperature, excessive vegetative growth, decrease in relative humidity, water stress at the time of flowering, overheating, excessive nitrogen fertilization and phytosanitary products that damage the flower. - Leaf yellowing and wilting: these are soon manifested by older leaves: the leaf turns to yellow at first and then it wilt with some reddish brown spots on the leaf stalk. This problem can be confused with leaf rust (Uromyces phaseoli), so a clinical analysis is necessary. The causing agent is not known, but some of the factors that influence their occurrence have been identified: sudden drop in relative humidity and water deficiencies. 9. HARVEST The harvest of green beans is manual, which significantly increase its labor cost. The physiological moment or time of harvest is very important in increasing commercial yield. The market is very demanding and it demands fruits with tender pods (but not much), with slightly marked grains. If the pods are harvested beyond the point of commercial maturity, they lose quality and value for being hard and fibrous. The frequency of harvest varies between 7 and 12 days, depending on the variety and growing season. Delays in harvesting cause losses: weight reduction and loss of market value. In dwarf or bush beans, harvesting may last from 50 to 90 days and in pole beans, from 65 to 95 days. Currently, fresh markets are supplied practically all year. The harvest of bean for grains is done mechanically and its cultivation should be done on large surfaces with suitable varieties.
10. NUTRITIONAL VALUE
Author: Infoagro
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