7. PESTS AND DISEASES
7.1. Pests
-Spotted spider mite (Tetranychus urticae (Koch) (Acarina: Tetranychidae), T. Turkestani (Ugarov & Nikolski) (Acarina: Tetranychidae) and T. ludeni (Thatcher) (Acarina: Tetranychidae))
The first species is the most common cited in protected horticultural crops, but the biology, ecology and damage are similar, so the three species are addressed jointly.
It develops on the underside of the leaves causing discoloration, pits or yellowish spots in the beam can be seen as the first symptoms.
With further drying occurs populations or even foliation. The most serious attacks occur in the early growth stages. High temperatures and low relative humidity favor the development of the pest.
Preventive control and cultural techniques
-Structures and soil disinfection prior to planting in plots with a history of spider mites.
-Elimination of weeds and crop residues.
-Avoid excessive nitrogen.
-Monitoring of crops during the early stages of development.
Biological control
Main prey species of eggs, larvae and adults of spider mites: Amblyseius californicus, Phytoseiulus persimilis (used in native and loose), Feltiella acarisuga (native species).
Chemical Control
Active ingredients: abamectin, summer oil, acrinathrin, amitraz, amitraz + bifenthrin, bifenthrin, bromopropylate, dicofol, dicofol + tetradifon, dicofol + hexythiazox, dinobuton, dinobuton + tetradifon, dinobuton + sulfur fenbutestan, fenpyroximate, hexythiazox, propargite, tebufenpyrad , tetradifon.
-Whitefly (Trialeurodes vaporariorum (West) (Homoptera: Aleyrodidae) and Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae))
The young parts of plants are colonized by adults, making the stakes on the undersides of leaves. Of these the first larvae emerge, they are mobile. Having fixed on the ground pass through three larval stages and a pupal stage, the latter characteristic of each species. Direct damage (yellowing and weakening of the plants) are caused by larvae and adults feed, sucking the sap from the leaves. Indirect losses are due to the proliferation of bold on food produced in molasses, staining and depreciating the fruits and hindering the normal development of plants. Both types of damages become important when population levels are high. Another is the indirect damage that occurs due to virus transmission. Trialeurodes vaporariorun is transmitting yellowing virus in cucurbits. Bemisia tabaci transmitter is potentially a greater number of viruses in horticultural crops and currently acts as a transmitter of leaf roll virus yellow tomato (TYLCV), known as “virus of the spoon.”
Preventive control and cultural techniques
-Placement of mesh in the bands of the greenhouses.
-Cleaning of weeds and crop residues.
-Do not combine in the same greenhouse crops.
-Do not leave the buds at the end of the cycle, as the young shoots attract whitefly adults.
-Yellow color trapping.
Biological control by natural enemies
Major parasites of whitefly larvae:
- Trialeurodes vaporariorum. Fauna native assistant: Encarsia formosa, Encarsia transvenous Encarsia lutea, Encarsia tricolor, Cyrtopeltis tenuis. Fauna auxiliary used in feed: Encarsia formosa, Eretmocerus californicus and Eretmocerus sineatis.
- Bemisia tabaci. Fauna native assistant, Eretmocerus mundus, Encarsia transvenous Encarsia lutea, Cyrtopeltis tenuis. Auxiliary fauna used in feed: Eretmocerus californicus.
-Aphid (Aphis gossypii (Sulzer) (Homoptera: Aphididae) and Myzus persicae (Glover) (Homoptera: Aphididae))
Aphid species are the most common and abundant in greenhouses. Polymorphisms with winged and wingless females of viviparous reproduction. Apterous forms of the first black traps present in the body green or yellow, while those of Myzus are completely green (sometimes brown or pink). Form colonies and distributed in foci that are scattered, mainly in spring and autumn, with winged females.
Preventive control and cultural techniques
-Placement of mesh in the bands of the greenhouse.
-Elimination of weeds and debris from the previous crop.
-Yellow color trapping.
Biological control by natural enemies
-Native predatory species: Aphidoletes aphidimyza.
-Native parasitoid species: Aphidius matricariae, Aphidius colemani, Lysiphlebus testaicepes.
-Species used in loose parasitoids: Aphidius colemani.
Chemical Control
Active substances acephate, alpha-cypermethrin, bifenthrin, carbosulfan, cypermethrin, cypermethrin + sulfur, fenitrothion + cypermethrin, cypermethrin + methomyl, deltamethrin, deltamethrin + heptenofos, endosulfan, endosulfan + methomyl, endosulfan + pirimicarb, esfenvalerate, fenitrothion + esfenvalerate, etofenprox , etofenprox + methomyl, fenitrothion, fenitrothion + fenpropathrin, fenitrothion + fenvalerate, fenpropathrin, fenvalerate, flucythrinate, phosalone, imidacloprid, lambda cyhalothrin, pirimiphos methyl, methomyl, methomyl + permethrin, methomyl + piridafention, permethrin, pirimicarb, propoxur.
-Thrips (Frankliniella occidentalis (Pergande) (Thysanoptera: THRIPIDAE))
Adults colonize crops put into making the plant tissues in leaves, fruits, and preferably in flowers (they flower), where we find the highest levels of population of adults and larvae hatched from the stakes. The direct damage caused by feeding larvae and adults, especially on the undersides of the leaves, leaving a silvery in the affected organs which then become necrotic. These symptoms may be seen as affecting fruit and when very large sheets. Indirect damage is the most important charges and is due to transmission of tomato spotted wilt virus (TSWV).
Preventive control and cultural techniques
-Placement of mesh in the bands of the greenhouse.
-Cleaning of weeds and crop residues.
Trapping-blue color.
Biological control by natural enemies
Auxiliary fauna indigenous: Amblyseius barkeri, Aeolothrips sp., Orius spp.
Chemical Control
Active ingredients: Atrina, cypermethrin, cypermethrin + sulfur, cypermethrin + chlorpyrifos-methyl, chlorpyrifos-methyl, deltamethrin, fenitrothion, formetanate, methiocarb.
Leafminers (Liriomyza trifolii (Burgess) (Diptera: Agromyzidae), Liriomyza bryoniae (Diptera: Agromyzidae), strigata Liriomyza (Diptera: Agromyzidae), Liriomyza huidobrensis (Diptera: Agromyzidae))
Adult females made the stakes in the young leaf tissue, where it begins to develop a larva that feeds on the parenchyma, causing the typical galleries. The shape of the galleries is different, though not always distinguishable, between species and crops. Once the larval development, the larvae emerge from the leaves to pupate in the soil or leaves, to subsequently lead to adults.
Preventive control and cultural techniques
-Placement of mesh in the bands of the greenhouse.
-Elimination of weeds and crop residues.
-In severe attacks, remove and destroy the lower leaves of the plant.
-Yellow color trapping.
Biological control
-Native parasitoid species: Diglyphus isaea, Diglyphus minoeus, Diglyphus crassinervis, Chrysonotomyia formosa, Hemiptarsenus zihalisebessi.
-Single parasitoid species used in: Diglyphus isaea.
Chemical Control
Active ingredients: abamectin, cyromazine, pyrazophos.
-Caterpillars (Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), Spodoptera litoralis (Boisduval) (Lepidoptera: Noctuidae), Heliothis armigera (Hübner) (Lepidoptera: Noctuidae), Heliothis Peltigera (Dennis and Schiff) (Lepidoptera: Noctuidae), Chrysodeisis chalcites (Esper) (Lepidoptera: Noctuidae), Autographa gamma (L.) (Lepidoptera: Noctuidae))
The main difference among species in the larval stage can be seen in the number of false abdominal legs (5 in Spodoptera and Heliothis and 2 and Chrysodeixis Autographa), or in the form of moving in and Chrysodeixis Autographa arching the body (caterpillars camel). The presence of setae (“hairs” long) on the surface of the body of the larva of Heliothis, or dark brown color, especially legs and head, the caterpillars of Spodoptera litoralis, also differs from other species.
The biology of these species is quite similar, passing through egg, larval and pupal stages 5-6. Eggs are laid on leaves, preferably on the underside, in Plaston with a large number of species of the genus Spodoptera, while others do in isolation. The damage is caused by larval feeding. In Spodoptera and Heliothis pupae in the soil is made ??and chalcites Chrysodeixis and Autographa gamma, in the leaves. The adult moths are nocturnal and crepuscular.
The damage can be classified as follows: damage to the vegetation (Spodoptera, Chrysodeixis), damage to fruit (Heliothis and Spodoptera) and damage on the stems (Heliothis and Ostrinia) that can reach blind plants.
Preventive control and cultural techniques
-Placement of mesh in 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, which may cause irreversible damage.
Biological control by natural enemies
Native-Parasites: Apantelles plutellae.
Pathogen-native: nuclear polyhedrosis virus of S. exigua.
-Biological Products: Bacillus thuringiensis.
Chemical Control
Active substances acephate, alpha-cypermethrin, amitraz + bifenthrin, Bacillus thuringiensis (delta-endotoxin). Bacillus thuringiensis (kurstaki Var.), Bacillus thuringiensis (Var. aizawai), betaciflutrin, bifenthrin, cyfluthrin, cypermethrin, cypermethrin + sulfur fenitrothion + cypermethrin, cypermethrin + methomyl, chlorpyrifos, deltamethrin, esfenvalerate, esfenvalerate + fenitrothion, esfenvalerate + methomyl, etofenprox, etofenprox + methomyl, fenitrothion, fenitrothion + fenpropathrin, fenitrothion + fenvalerate, fenvalerate, flucythrinate, flufenoxuron, lambda cyhalothrin, pirimiphos methyl , methomyl, methomyl + piridafention, methomyl + permethrin, permethrin, propoxur, tau-fluvalinate, teflubenzuron, thiodicarb,, tralomethrine, trichlorfon.
-Nematodes (Meloidogyne javanica, M. javanica, M. arenaria and M. incognita (Tylenchida: HETERODERIDAE))
Affect virtually all horticultural crops, producing the typical nodules on the roots that give the common name “Batatilla.” Roots penetrate the ground. The females to be fertilized eggs are filled with taking a look into the roots globose. This coupled with hypertrophy in the tissues that produce the same results in the formation of the typical “beads.”
These injuries cause obstruction of blood vessels and prevent the absorption by the roots, resulting in reduced plant growth and the onset of symptoms of wilt in green in the heat of the day, chlorosis and stunting. Stands are distributed or lines and are easily transmitted by irrigation water, with the shoe, with the tools and any conveyance of land. In addition, nematodes interact with other pathogens, either actively (as vectors of viruses) or passively facilitating the entry of bacteria and fungi from the wounds they have caused.
Preventive control and cultural techniques
-Use of resistant varieties.
-Soil disinfection in plots with previous attacks.
-Use of healthy seedlings.
Biological control
-Biological products: prepared on the basis of fungus Arthrobotrys irregularis
Control by physical methods
Steam-sterilization.
-Solarization, which is to raise the soil temperature by placing a sheet of clear plastic over the soil for at least 30 days.
Chemical Control
Active ingredients: benfuracarb, cadusafos, carbofuran, dichloropropene, ethoprophos, fenamiphos, oxamyl.
7.2. Diseases
- “Ash” or powdery mildew of cucurbits (Sphaerotheca fuliginea (Schelecht) Pollaccia. Ascomycetes: ERYSIPHALES)
The symptoms seen are white powdery spots on the surface of the leaves (beam and back) that will cover the whole vegetative apparatus coming to invade the whole sheet, also affects stems and petioles and even fruit in very strong attacks. The attack leaves and stems become yellowish and dry. The weeds and other cucurbit crops and crop residues would be the sources of inoculum and the wind is responsible for transporting the spores and spread the disease. The temperature is in the range of 10-35 ° C, with the optimum around 26 ° C. The optimum relative humidity is 70%.
Preventive control and cultural techniques
-Elimination of weeds and crop residues.
-Use of healthy seedlings.
-Conduct treatments to structures.
Gray rot (Botryotinia fuckeliana (de Bary) Whetrel. Ascomycetes: Helotiales. Anamorph: Botrytis cinerea Pers)
Parasite that attacks a wide range of plant species, affecting all protected horticultural crops, being able to behave as parasite and saprophyte. In seedling damping-off occurs. In leaves and flowers are produced brown lesions. In fruit soft rot occurs (more or less water depending on the tissue), which shows the gray mycelium of the fungus.
The main sources of inoculum are the conidia and the plant residues that are dispersed by wind, splashing rain, drops of condensation on plastic and irrigation water. The temperature, relative humidity and phenology influence the disease separately or together. The optimum relative humidity hovers around 95% and temperature between 17 ° C and 23 ° C. Infected and detached petals act dispersing the fungus.
Preventive control and cultural techniques
-Elimination of weeds, crop residues and infected plants.
-Be especially careful in pruning, making clean cuts flush with the stem. If possible when relative humidity is not too high then a paste and apply fungicide.
-Control the levels of nitrogen.
-Use plastic covers on the gases that absorb ultraviolet light.
-Use proper orchard to allow aeration.
-Appropriate management of ventilation and irrigation.
Tags: Atrina, chlorpyrifos-methyl, cypermethrin, cypermethrin + chlorpyrifos-methyl, deltamethrin, fenitrothion, formetanate, methiocarb., sulfur, zucchini