HOW TO PREVENT AND COMBAT THE MOST COMMON PESTS AND DISEASES IN THE MELÓN CULTIVATION

Hello friends of the farms in this opportunity I am going to talk about the melon is a creeping plant that belongs to the family of Cucurbitaceae. The care and cultivation of the melon is very conditioned by the climate, giving its production good results if this is the right one. Despite all the cares that can be provided to the melon, it can be affected by different types of pests and diseases. We show you how to prevent and fight the most common pests and diseases of the melon.

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PESTS OF MELON CULTIVATION

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RED SPIDER
Red spider is the most common pest among horticultural crops. It develops on the underside of the leaves of the melon plant, causing it to turn yellow and end up drying. The most serious attack occurs during the development of the plant, with high temperatures and humidity, which favors its development. Solution: disinfects the soil before planting by choosing an appropriate fungicide and eliminates weeds and remains of previous crops. Another option is to introduce into the habitat of the red spider natural predators that end with it.
The first species cited is the most common in protected horticultural crops in the province of Almeria, but the biology, ecology and damage caused are similar, so that the three species are addressed together.
It develops on the underside of the leaves causing discolorations, punctures or yellowish spots that can be seen in the beam as first symptoms. With greater populations, desiccation or foliation is produced.
The most serious attacks occur in the first phenological stages. High temperatures and low relative humidity favor the development of the pest. In bean and watermelon with high levels of pest damage can occur in the fruits.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Disinfection of structures and soil prior to planting in plots with a history of red spider.
Elimination of weeds and crop residues.
Avoid excess nitrogen.
Surveillance of crops during the first stages of development.

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WHITE FLY
The whitefly attacks the most tender parts of the melon plant. On the underside of the leaves it lays eggs from which larvae later emerge. The damage caused by the whitefly in this vegetable is yellowing and weakening when the larvae hatch, which feed on the sap. The fruits begin to suffer spots and stop developing. Solution: cleans the weeds, choosing a herbicide and introducing natural enemies of the white fly into its habitat.
The young parts of the plants are colonized by the adults, making the placements on the underside of the leaves. From these emerge the first larvae, which are mobile.
After looking at the plant go through three larval stages and one pupa, the latter characteristic of each species. The direct damages (yellowing and weakening of the plants) are caused by larvae and adults feeding, absorbing the sap from the leaves.
The indirect damages are due to the proliferation of bold on the molasses produced in the food, staining and depreciating the fruits and hindering the normal development of the plants. Both types of damage become important when population levels are high. Other indirect damages are produced by the transmission of viruses.
Trialurodes vaporariorun is a transmitter of yellowing virus in cucurbits. Bemisia tabaci is potentially transmitter of a greater number of viruses in oat crops and currently acts as a transmitter of tomato yellow curl virus (TYLCV), known as "spoon virus".

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Placement of meshes in the greenhouse bands.
Cleaning of weeds and crop remains.
Do not associate crops in the same greenhouse.
Do not abandon the shoots at the end of the cycle, as young shoots attract whitefly adults.
Placement of yellow chromatic traps

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PULGON
Aphids are usually the most abundant pests in greenhouses, eventually forming colonies that disperse in the spring. They feed on the sap of the plant, causing its weakening and lack of development. Solution: begins by eliminating weeds and remains of previous crops and introduces predator species of the aphid.
Aphis gossypii (Sulzer) and Myzus persicae (Glover). They are the most common and abundant aphid species in greenhouses. They present polymorphism, with winged females and apterous viviparous reproduction.
The apterous forms of the first have black siphons in the green or yellowish body, while those of Myzus are completely green (sometimes brown or pink).
They form colonies and distribute themselves in foci that disperse, mainly in spring and autumn, through the winged females.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Placement of meshes in the greenhouse bands.
Elimination of weeds and remains of the previous crop.
Placement of yellow chromatic traps.

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TRIPS
These insects attack the cultivation of the melon through its leaves, flowers and fruits where they make their sunsets. The larvae that hatch feed on the leaves leaving them necrotic and the same thing happens with the fruits. Solution: clean the weed growing area and place blue chromatic traps to attract this pest and eliminate it.
Adults colonize the crops by placing them inside plant tissues in leaves, fruits and, preferably, in flowers (they are flowers), where the highest levels of adult population and larvae born from the laying are located.
The direct damages are produced by feeding larvae and adults, especially on the underside of the leaves, leaving a silvery appearance on the affected organs that then become necrotic. These symptoms can be seen when they affect fruits (especially in pepper) and when they are very extensive in leaves).
The sunsets can be observed when they appear in fruits (aubergine, bean and tomato). The indirect damage is the one that accuses greater importance and is due to the transmission of tomato tanning virus (TSWV), which affects pepper, tomato, eggplant and bean.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Placement of meshes in the greenhouse bands.
Cleaning of weeds and crop residues.
Placement of blue chromatic traps.

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LEAF MINERS
These insects make their placement in the young leaves, where the larvae that emerge feed on the leaves forming galleries in them. Solution: eliminate weeds and crop remains and destroy the affected plants.
The adult females make the inserts in the tissue of the young leaves, where a larva that feeds on the parenchyma begins to develop, causing the typical galleries. The shape of the galleries is different, although not always distinguishable, between species and crops. Once the larval development is finished, the larvae leave the leaves to pupate, in the soil or in the leaves, to give place later to the adults.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Placement of meshes in the greenhouse bands.
Elimination of weeds and crop residues.
In strong attacks, eliminate and destroy the lower leaves of the plant.
Placement of yellow chromatic traps.

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CATERPILLARS
The caterpillars deposit their eggs on the underside of the leaves, causing serious damage to the plant. They also attack fruits and stems. Solution: eliminate weeds and get rid of crop residues, in addition to burning infected plants.
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 and Chrysodeixis), or in the form of moving in Autographa and Chrysodeixis arching the body (caterpillars camel).
The presence of silks (long "hairs") on the body surface of the Heliothis larvae, or the dark brown coloration, especially of the legs and head, in the caterpillars of Spodoptera litoralis, also differentiates them from the rest of the species.
The biology of these species is quite similar, going through egg states, 5-6 larval stages and pupa. The eggs are deposited on the leaves, preferably on the underside, in plastones with a high number of species of the genus Spodoptera, while the others do so in isolation.
Damage is caused by larvae feeding. In Spodoptera and Heliothis the pupa is made in the soil and in Chrysodeixis chalcites and Autographa gamma, in the leaves. Adults are moths with nocturnal and crepuscular habits.
Damage can be classified as follows: damage to vegetation (Spodoptera, Chrysodeixis), damage to fruits (Heliothis, Spodoptera and Plusias in tomato, and Spodoptera and Heliothis in pepper) and damage to stems (Heliothis and Ostrinia) that can blind the plants.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Placement of meshes in the greenhouse bands.
Elimination of weeds and crop residues.
In strong attacks, eliminate and destroy the lower leaves of the plant.
Placement of pheromone traps and light traps.
Monitor the first stages of crop development, in which irreversible damage can occur.

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NEMÁTODOS
The nematodes penetrate from the ground into the roots, atrophying them. This attack obstructs the root system, damaging its tissue and ending by withering the melon plant, causing it to dwarf it. These insects are transmitted through irrigation water, work tools or pruning and any element that has had contact with the earth. Solution: Be sure to use a resistant variety of melon, disinfect the soil before planting and use healthy stock. You can also steam sterilize the crop or use solarization (raise the soil temperature).
In horticultural plants in Almeria, the species M. Javanica, M. Arenaria and M incognita have been identified. They affect practically all the horticultural crops, producing the typical nodules in the roots that give the common name of "batatilla". They penetrate the roots from the ground.

The females when fertilized are filled with eggs taking a globular appearance inside the roots. This together with the hypertrophy that they produce in their tissues, results in the formation of the typical "rosaries".

These damages cause the obstruction of vessels and impede the absorption by the roots, translating into a lower development of the plant and the appearance of wilt symptoms in green in the hours of more heat, chlorosis and dwarfism.

They are distributed by stands or lines and are easily transmitted by irrigation water, footwear, implements and any means of land transport. In addition, nematodes interact with other pathogenic organisms, either actively (as vectors of viruses), or passively facilitating the entry of bacteria and fungi by the wounds they have caused.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Use of resistant varieties.
Disinfection of the soil in plots with previous attacks.
Use of healthy seedlings.

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MOST COMMON DISEASES IN MELON CULTIVATION

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"ASHES" OR OIDIUM: ASCOMYCETES: ERYSIPHALES.
The symptoms that are observed are white powdery spots on the surface of the leaves (leaves and undersides) that cover the entire vegetative apparatus, invading the whole leaf, it also affects stems and petioles and even fruits in very strong attacks.
The leaves and stems attacked turn yellowish and dry. The weeds and other crops of cucurbits, as well as crop remains, would be the sources of inoculum and the wind is responsible for transporting the spores and dispersing the disease.
The temperatures are in a range of 10-35 ºC, with the optimum around 26 ºC. The optimum relative humidity is 70%. In melon have been established three races (Race 1,2 and 3,) standing out in Malaga and Almeria races

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Elimination of weeds and crop residues.
Use of healthy seedlings.
Perform treatments to structures.
Use of melon varieties with partial resistance to the two races of the pathogen.

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MILDEW
The symptoms appear only in leaves as yellowish spots of an angular shape delimited by the nerves. On the underside there is a violet gray felt that corresponds to the spores góforos and esporangios of the fungus. Later, the spots become necrotic, taking on a parchment-like appearance and affecting the entire leaf that dries, remaining attached to the stem.
Dispersion: by means of winds, rains, drops of condensation, etc. Optimal conditions of development: high relative humidity, a period of liquid water is indispensable in the leaf, optimum temperature between 20 and 25 ºC, although the limits are between 8 and 27 ºC.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Elimination of weeds and crop residues.
Avoid excess humidity, ventilating the greenhouse.
Plantation frame not very dense.
Remove the affected plants at the end of the crop.

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VASCULAR DISEASES

Yellow type: yellowing of leaves. They begin with the yellowing of veins on one side of the leaves that progresses affecting the limbus. In stems, longitudinal necrotic striae from which rubber is exuded are observed, later the fungus sporulates on the necrotic zones forming pink spores. In the cross section of the stem a darkening of the vessels is observed.

Type Wilt: Sudden green wilt of the plants without yellowing or developing color.

PREVENTIVE AND CULTURAL TECHNICAL METHODS
Crop rotation gradually reduces the pathogen in infected soils.
Eliminate diseased plants and crop remains.
Use certified seeds and healthy seedlings.
Use of resistant varieties
Disinfection of structures and work tools
Solarization.

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GUMMY STEM CHANCRO
In seedlings it mainly affects the cotyledons in which it produces rounded brownish spots, in which black and brown spots are observed distributed in the form of concentric rings. The cotyledon ends up drying, producing lesions in the area of ​​the insertion of the latter with the stem.
The most frequent symptoms in melon, watermelon and cucumber are those of "gummy chancre of the stem" that are characterized by a beige lesion on the stem, covered with pycnidia and often produce gummy exudations near the lesion.
In the aerial part causes wilting and death of the plant. In zucchini, these beige spots also appear on leaf petioles and nerves, and there are also some spots in the limb of the house that at the beginning are yellow and enlarge quickly turning brown. Often the interior of this stain breaks, remaining perforated. In cucumber and zucchini crops attacks to the fruit take place, which are characterized by strangulation of the area of ​​the stylar scar, which is covered with pycnidia. It can be transmitted by seeds. The rest of the harvest is a primary source of infection and the spores can survive in the soil or in the stems and in the structure of the greenhouses, being frequent the points of infection in the wounds of prunings and grafts.
The temperature of development of the disease is 23-25 ​​ºC, favored with high relative humidity, as well as excess of nitrogen fertilizer. The high light intensities decrease it.

PREVENTIVE AND CULTURAL TECHNICAL METHODS

• Use healthy seed.
  Eliminate crop residues both around and inside the greenhouses.
  Disinfection of greenhouse structures.
  Control of ventilation to reduce relative humidity.
  Avoid excess moisture in soil. Remove droppers from the foot of the plant.
  The infected fruits and the pruning remains should be removed from the greenhouse.
  Perform the pruning correctly.

ALTERATIONS OF FRUIT OF MELON

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DEFORMATIONS

They can have their origin in one or more of the following causes: bad pollination, water stress, incorrect use of certain filter regulators used to improve the fattening and fruit set of the melon, poor fertilization due to inactivity or pollen insufficiency, adverse weather conditions , etc.

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SUNSHINE
Whitish spots on fruits caused as a result of the direct incidence of sunlight associated with high temperatures.

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RIVEN
It is mainly produced longitudinally. It is caused by imbalances of environmental humidity or irrigation (excess water or water stress in the phases prior to final maturation), by sudden changes in the EC of the nutrient solution, usually because it is very low at the time of maturation , or by keeping the fruit mature too long in the plant.

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SPOTS
They are more evident in melons of "Yellow type", presenting brown spots dispersed by the surface of the fruit that have their origin in conditions of high relative humidity, in burns caused by the phytosanitary treatments, or deposits of pollen.

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ABORTION
The abortion of newly set fruit occurs due to an excessive load of fruits (natural thinning of the plant) or a lack of nutrients and water, or both.

SOURCE:
http://canales.hoy.es/canalagro/datos/frutas/frutas_tradicionales/melon6.htm
http://articulos.infojardin.com/huerto/cultivo-melon-melones.htm
https://www.phytoma.com/sanidad-vegetal/avisos-de-plagas/melon-plagas-y-enfermedades-mayo-2017

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