Peanut (Arachis hypogaea L.), legume native to South America, and cultivated in various Tropical World Regions, by its wide adaptability to a great diversity of environments. In Brazil, São Paulo and the capital producer, contributing around 70-80% of National Production Estimated at 120-150 thousand tons Annual (MORAES, 2006).
Annual herbaceous plant in the Fabaceae family, whose seeds contains around 25% protein and 45-50% of edible oil. The cultivated species and in various countries around the world in north and south hemisphere, both by small family farmers how for producers with high technological level. In some asian countries, peanut production is intended to oil, used in cuisine. In western countries, including Brazil, the product is used primarily as food, at the confectionery market.
The peanut plant has as peculiar characteristic the production of underground fruits. The plant, once fertilized, emits a tassel or spur (gynophore) that grows towards the ground, penetrating it. The fertilized ovary, located at the tip of the spur, develops under these conditions, under the surface of the soil, forming the pod.
The specie, typical warm climates, adapts to a wide climate range in tropical and subtropical regions, with exception of the ones overly humid and develops well in regions or cultivation stations where the minimum temperatures do not fall below 15°C. With an adequate level of fertility, light and well drained soils are preferred for cultivation, it can also be grown on soils with a certain clay content.
Cultivars
These are the IAC (Agronomic Institute of Campinas) currently recommended for planting:
IAC Tatu ST: Suitable for family crops in semi-mechanized system; the plant is erect, like Valencia, 90-110 day cycle, pods of three to four seeds of small size and red film; production potential up to 4500 kg ha-¹ of pods; in São Paulo, serves a small-scale demand, niche market for peanuts sold in shell or peeled raw state.
IAC 503: Suitable for technified systems, creeping sized, moderately resistant to leaf diseases, 140-day cycle; pods with two elongated seeds of medium to large, light brown seeds; production potential of up to 6,500 kg ha-¹ of pods; the seeds have the characteristic “high oleic” (around 80% of this fatty acid, responsible for providing the product a “shelf period” longer).
IAC 505: Suitable for technified systems, creeping sized, moderately resistant to leaf diseases, 130-140 day cycle; pods with two medium-sized seeds (commercial standard Runner), light brown film; production potential: up to 6,500 kg ha-¹; This cultivar is distinguished by higher oil content than other varieties (about 50%), making it attractive for both the food market and for projects for the production of oil; the seeds have the characteristic “high oleic”.
IAC OL 3: Suitable for technified systems, creeping size, 130-day cycle, to better fit than the previous renewal areas cane; pods with two medium-sized seeds large pink color film; production potential up to 7000 kg ha-¹; the seeds have the characteristic “high oleic”.
IAC OL 4: Indicated for technical systems, low size, the 125-130 day cycle, allows better adjustment of its cultivation in the cane renewal areas; Pods with two seeds of medium size (Runner pattern), pink color film; Productive potential: up to 7,000 kg ha-¹; The seeds have the characteristic “high oleic”.
In order to forecast costs and profitability, the expected average productivity for the cultivar IAC Tatu ST is between 3,500 and 4,000 kg ha-¹ of pods, under the conditions of the state of São Paulo. For the low-lying cultivars listed here, the average productivity to be considered is between 4,500 and 5,000 kg ha-¹.
Planting
Peanut seeds are vulnerable to soil fungi infections in their germination and emergence; Thus, it is essential to treat them with fungicides. The best season for planting in the climatic conditions of the state of São Paulo is between October and November. The cultivar IAC Tatu ST can be planted in a second season (February-March), but the culture is subject to drought at the end of the cycle; It is not recommended to plant low-lying cultivars at this time.
Pest Control
Silage thrips (Enneothrips flavens Moulton) is the pest of the greatest economic expression of culture in the state of São Paulo; The red-necked caterpillar (Stegasta bosquella Chambers) is also frequent and can cause significant damage to plants; Both attack the shoots (young leaves), damaging the growth of the plant. The thrips can be chemically controlled by treatment of the seeds with thiamethoxan or imidacloprid and, after 30 days of sowing, with foliar sprays of neonicotinoids or organophosphates, every 15 days. Without seed treatment, sprays should start at 10-15 days after sowing. When the conditions allow, the control of thrips can be accomplished by monitoring the insect by sampling leaflets, evaluating the infestation to determine the need for application of the insecticide. In this case, in erect cultivars, it is recommended to spray when 30% of leaflets present the insect and, in low cultivars, when the infestation is 40%. In the case of the red-necked caterpillar, chemical control is done with insecticides based on pyrethroids or organophosphates. In the control by monitoring, it is recommended to perform the spraying when the level of infestation reaches one caterpillar for every 5 pointers sampled. Other insects that may eventually cause damage to the shoot are spittlebugs, mites and other species of caterpillars, which are controlled, when they occur, with appropriate insecticides. Infestations of Diabrotica larvae and bedbugs (brown and black) can cause damage to the roots or to the pods and seeds in formation, in the soil. Damage caused by Diabrotica larvae can be prevented through the control of adult insects via the leaf. The black bug can cause significant damage as it damages the grains in formation. In regions or environments in which its occurrence is frequent, the insect should be monitored by excavating the soil at 30 cm in several areas throughout the crop, when it is in the phase of grain filling; With 2 insects, it is recommended to apply chlorpyrifos to the soil in a directed jet.
Harvest
At the time of maturation, and knowing the cycle of the cultivar, constantly monitor the field and sample plants observing the pods and grains to define the best time of harvest. For the cultivar IAC Tatu ST and others of the Valencia type, to carry out the arranchance of the plants when 70% of the pods present the characteristic dark spotting in their interior. For low cultivars, start the scratching when 60% of the pods show darkening of the endoderm (surface of the bark just below the epidermis). In technified crops, the ripening and weeding of the plants are carried out by puller / inverter machines. In family plantations, cut the root under the pods with a blade drawn by an animal or tractor, and then weed the plants manually, with the pods facing upwards. The plants should remain encircled in the sun until complete drying, when there is no artificial drying. If there is artificial drying, the period of drying in the field is smaller, enough to allow dislodging with the picking machine. Artificial drying can be done in silo dryers or perforated bottom carts. In both cases the air is forced between the pods deposited in bulk in the drying compartment.
Crop rotation
The peanut is efficient in taking advantage of the residual fertilization of the previous crop, besides being practically self-sufficient in nitrogen through symbiotic fixation. The crop is also known for its tolerance to various species and breeds of nematodes, contributing to reduce the population of these pathogens in infested areas. In São Paulo, its cultivation is conducted predominantly in rotation with sugarcane and pasture. Its planting in the cane renewal areas favors the main crop, among other benefits, the reduction of weed infestation, besides leaving residues of nutrients in the soil, contributing to reduce the costs of implantation of sugarcane plantations. In the case of rotational planting with cane, it is necessary that the peanut cultivars be compatible with the duration of the canevial renewal period.
Preventive control of aflatoxin
Aflatoxin is a carcinogenic toxic substance for humans and animals, which may be present in peanuts and their derivatives; It is produced by fungi of the genus Aspergillus and Penicillium that survive naturally in the soil and can infect the peanut and produce the toxin, both before and after harvest, and during storage. Infections by these fungi, when peanuts are still in the soil, are especially favored by periods of drought during the maturation phase of the pods; Thus, regions prone to water stress should be avoided; On the other hand, the use of irrigation provides favorable conditions for the production of quality peanuts, in addition to the preventive practices to be followed. For the production of peanuts free of this toxin, several measures must be adopted: a) control pests and diseases of plants, to produce healthy and resistant pods to these fungi; B) to harvest the peanut when it is fully ripe and, after the weeding of the plants, to enclose them with the pods facing upwards, without contact with the ground; C) drying the harvested peanuts until the moisture in the grains is reduced to 8%; D) in technical systems, the use of artificial dryers is the recommended practice; In small family farms, the drying of the pods, after removal from the plants, can be done efficiently in a terreiro; E) never bag, stack or store peanuts with more than 8% moisture; F) After peeling, proceed to the selection of the grains, removing the damaged, lame, immature or poor appearance. For greater guarantee of the sanity of the product, to use laboratories specialized in aflatoxin analysis; For consumers, preferentially purchase products that contain a seal or quality certificate.
Bibliographic references
Authors
Ignácio José de Godoy – Centro de Grãos e Fibras / IAC, Campinas, SP;
Denizart Bolonhezi – Polo Apta Centro Leste, Ribeirão Preto, SP;
Marcos Doniseti Michelotto – Polo Apta Centro Norte, Pindorama, SP;
Everton Luis Finoto – Polo Apta Centro Norte, Pindorama, SP;
Rogério Soares de Freitas – Polo Noroeste Paulista, Votuporanga, SP.
Moraes de, S. A. Amendoim: Principais doenças, manejo integrado e recomendações de controle. 2006. Artigo em Hypertexto. Disponível em:<http://www.infobibos.com/Artigos/2006_2/amendoim/Index.htm>.
FONTE: www.abicab.org.br – modified.