Reduction of Pest Organisms and Improvement of the Quality and Biosecurity of Edible Fruits of Chayote (Sechium edule (Jacq.) Sw.)

Abstract

Chayote (Sechium edule (Jacq.) Sw.) (Cucurbitaceae) is a vegetable native to backyard gardens that has evolved as an export product in the last 20 years. The producing countries are Mexico, Costa Rica, the Dominican Republic, and recently some Mediterranean countries in Europe. Its commercial success has extended the cultivation areas, and pest organisms have been identified that attack different organs of the plant, affecting profitability, health, and safety. The lack of accurate knowledge about damage caused to the plant generates errors and costs for its control due to wrong diagnoses and the use of pesticides of toxicological groups and doses that do not effectively control the pest organism. For this reason, it is essential to have the identification of the main pest organisms that attack each organ of the chayote plant, in order to ensure timely, adequate, socially, and environmentally responsible management that allows sustaining productivity and obtaining quality fruits. This chapter graphically describes, for the first time, the main pest organisms that limit the productivity of commercial chayote.

1. Introduction

The vegetable market is among the most dynamic areas of international trade in agricultural products, stimulated by the purchasing power and consumer interest in variety, freshness, convenience, and year-round availability. The main exporters of vegetables in the world are the Netherlands, Spain, China, France, Belgium, Canada, and Mexico, while the large importers are the European Union and the United States, which account for 50% of the world value of vegetable imports. In recent years, there has been an active commercial exchange between nations. This has had an impact on improving production systems but has also led to the promotion of more intensive agriculture that promotes the use of pesticides in order to avoid losses due to pest attacks.

Chayote [Sechium edule (Jacq.) Sw] (Cucurbitaceae) is among the main vegetables produced in Mexico, whose cultivation in 2011 covered 2147 ha [1]. However, like other cucurbits, chayote is attacked by pest organisms that cause losses of up to 30%. The ignorance of good crop management has led to excessive or incorrect use of pesticides that can generate problems of resistance of the organisms and residually in the fruit. Therefore, the objective of this work is to disseminate the identification in the field of the symptoms and main pests associated with the crop, in order to reduce or avoid the application of high-impact synthetic agrochemicals and to propose the use of pruning as a management practice that reduces the incidence of pest organisms associated with chayote for its evolution to organic farming [2, 3].

1.1 Chayote (Sechium edule)

The chayote fruit is a berry (Cucurbitaceae) and is a non-traditional export vegetable whose main use is for food. In Mexico, it is one of the main export vegetables, with a production of 178,228.63 t and yields ranging from 63.63 to 137 t ha⁻¹ [1]. This is taking into account that the cultivation cycle is 1 year and 6 months out of it are productive. Given the commercial success of chayote in North American markets, the intensive production area nationwide has increased in recent years, displacing other crops, which has caused certain organisms to become new pests.

Lack of knowledge about the biology and etiology of pests and diseases has promoted the inappropriate application of insecticides, fungicides, and acaricides, which has caused increased costs and the risk of developing resistance in organisms [4]. In Mexico, it is estimated that the use of these products has increased over time. In the year 2000, 50,000 tons of pesticides were consumed, while in 2006, there were 95,025 tons of pesticides [5].

The inappropriate use of these products represents a risk to human health, causing hormonal alterations, congenital malformations, mutagenic capacity, and different types of cancer [5]. Therefore, it is important to establish more efficient management strategies that reduce pesticide applications, expenditure on inputs, and the risk of poisoning both the applicator and consumers and which favor obtaining products of sustainable quality and low environmental impact.

The chayote production system consists of plantations established on a wood and wire structure that supports the productive vine of the plant. According to the agroclimatic region, plantation densities vary from 128 plants ha⁻¹ for cloud forest regions (1000–1450 m altitude), 600 and 800 plants ha⁻¹ in medium evergreen forest (800–600 m altitude), and up to 1300 plants ha⁻¹ in low deciduous forest (<500 m altitude). Each plant annually generates 52–58 boxes of 20 kg, equivalent to 1040–1160 kg ha⁻¹.

1.2 Pruning as an ecological practice

In chayote cultivation, one of the cultural practices that provide the greatest benefit in the relationship between quality and quantity of fruit per plant is pruning. This allows for regulating the luminosity and aeration in the support structure and favoring the health status of the plants since it eliminates leaves and vines with signs and symptoms of fungal infections, oomycetes, oviposition, and colonies of harmful insects (Figures 1 and 2).

Figure 1.

Panoramic view of a commercial chayote plantation.

Figure 2.

A: Leaf with insect eggs. B: Leaf with mildew. C: Leaf with ash. D: Leaf with aphid.

In the case of herbs such as the chayote plant, pruning is carried out in two ways: pruning horizontal growth vine and pruning vertical growth vine (Figure 3).

Figure 3.

A: The orchard is in the process of pruning, showing the difference in light entry in the pruned area. B and C: Biomass (leaves, fruits, and vines) removed during pruning and incorporated into the garden.

1.2.1 Pruning horizontal growth vines

Chayote is an annual herb of indeterminate growth native to the cloud forest. It naturally behaves like climbing grass on trees and bushes. In a cultivated form, it develops on a structure built of posts and wires in the shape of a grid that provides support. The growth is observed vertically or orthotropically when it ascends to the grid (2.2. m). It then does so horizontally or plagiotropically and advances forming a canopy by overlapping the vine of its own and neighboring plants (Figure 3).

Each horizontal vine presents the formation of a completely expanded leaf at the node, as well as a tendril, a rachis with staminate flowers, a pistillate flower, and a vegetative bud that can give rise to lateral branching. Thus, fruit production occurs linearly and unitarily at each node, and indeterminate growth generates vines of more than 30 m in length. Coupled with its overlap in the canopy, it forms a thick layer of foliage that obscures the lower part of the support structure, reducing the entry of light, which reduces the green color of the fruits. It also reduces yields due to the high number of old and unproductive vines.

A disadvantage of the above is the excess weight due to the biomass in the structure, which increases the impact of pathogens (fungi, bacteria) on fruits and leaves due to greater darkening, reduction in temperature, and less air circulation. Under these conditions, foliar applications (nutrients, fungicides, insecticides) do not reach the guidelines at the top of the canopy. Furthermore, when the fruits are not cut at the harvest index, they mature on the plant and can be hosts for borers (Diaphania nitidalis Stoll, D. hyalinata Linneo) (Figure 4), or be infected by fungi or bacteria that remain trapped in the vine net and become latent sources of contagion.

Figure 4.

Chayote fruit bored by Diaphania nitidalis Stoll.

Traditionally, the removal of leaves (defoliation) is carried out to improve the light and temperature conditions in the orchard, but leaving the old and unproductive vine does not remedy the production aspect. Therefore, the correct way to apply the concept of pruning in chayote is to eliminate the old or very mature vine, which can be recognized by a green-brown longitudinal stripe and is the thickest of the entire vine complex (Figure 5).

Figure 5.

A: Commercial chayote orchard without pruning. B: Pruned garden.

The “crown” cut is made in the vine located at the inflection they make when going vertical.

Horizontally, take care to do so 40 cm away from the inflection to prevent dripping sap from falling on the base of the plant, since it facilitates the germination of fungal spores and generates rot due to its nutritional richness. The cut should be done between 10:00 and 12:00 a.m. to reduce dripping and to accelerate the wilting of the leaves due to temperature, which helps the pruner to easily identify it.

In this way, the biomass weight is reduced, since the vine pieces have leaves, very thin and unproductive branches, and some small fruits. An advantage of the above is that, by not pruning the root area, the supply of water and nutrients (root–stem–leaves ratio) exceeds the aerial demand, which causes high emission of lateral branches from the nodes of the vine, which quickly reach sexual maturity and emit rachises of staminate and pistillate flowers that generate new fruits. This results in vigorous rejuvenation in the next 7–9 days after pruning in well-nourished plants.

The importance of pruning in commercial chayote orchards is observed in the stability and frequency of production reflected in fruit cuts, which are carried out twice a week to meet the harvest index of fruits at horticultural maturity (18 ± 2 days after anthesis). Another benefit of pruning is the reduction of health problems and applications of agrochemicals to control them, since the cut biomass is accompanied by fungi, bacteria, mites, insect eggs laid on leaves, infested fruits, or with borer larvae, among others.

The biomass cut during pruning should be left in the corridors to free up the fertilization zone, so that it degrades and is incorporated along with the grass that is regularly cut. In addition, pruning significantly reduces fruit staining and bleaching. Staining results from the contact of a senescent leaf attached to the fruit, which stains with humidity and resembles rust, while bleaching is the reduction of the green color attributed to darkening due to excess foliage in the canopy.

1.2.2 Pruning vertical growth vines

This work is carried out to select the number of vertical vines (orthotropic) that will reach the support structure (2.2 m) (Figure 6).

Figure 6.

A: Orchard without selection of pruning vine. B: Plant with pruned vine. C: Plant with three productive vines after pruning.

This action begins when two fruits containing the endocarp seed are planted, and once they germinate, the vines emitted from both are selected and only three remain throughout the plant.

2. Pests in chayote

A pest is one or a set of organisms belonging to one or different biological species that cause problems when they reach a certain density and cause a reduction in the quality or quantity of a good used by humans. Many plants are attacked and damaged by pests by competing, hosting or serving as food, or as a means of disease transmission. Damage can range from a slight decrease in the yield of a crop to complete destruction.

Some fungi and bacteria that cause infections only penetrate through the stomata or hydathodes (Figure 7).

Figure 7.

A, B, C, D: Penetration of fungi and bacteria through stomata in chayote leaves, development of powdery mildew on leaf blade. A: Stoma; B: Bacteria on adaxial leaf surface; C: Hyphae and reproductive structures of Pseudoperospora cubensis, invading through stomata; D: Conidiophores of Golovinomyces cichoracearum.

Many infections probably happen in greater proportion if the plants are surrounded by a thin film of water, but the guttation drops near the apices of the leaves also facilitate the germination of the spores and the penetration of infectious hyphae through natural openings. In the case of chayote, the leaves have stomata on both surfaces (adaxial and abaxial), which represent greater access sites for microorganisms such as fungi, oomycetes, and bacteria (Figure 7).

The fruit is a fleshy berry with light green epidermis, glabrous, with a single seed, and 95% of the fresh weight of the fruit is water, making it highly susceptible to mechanical damage and chafing. The presence of a high density of stomata on the epidermis (40 stomata/mm²) has been reported, which allows access to fungal and oomycete hyphae. In addition, the fruit is attacked by Coleoptera, Lepidoptera, and Diptera (Figures 8 and 9).

Figure 8.

A: Symptoms caused by Phytophthora capsici infection in chayote fruit. B and C: Scanning electron micrograph, surface of the epidermis with abundant sporangia. D: Fruit drilled by Diaphania nitidalis.

Figure 9.

A: “Arrocillo” (Diabrotica sp.) adults, female and male in copulation; the female is larger and lays her eggs on the ground near where the new chayote shoots emerge. B–D: Chayote roots infested by Diabrotica sp. larvae.

High populations of blind hens have been found feeding on chayote roots in which Phyllophaga sp. and Cyclocephala sp. have been observed. The genus Phyllophaga represents a greater risk, since the two genera differ in their feeding habits. For example, Phyllophaga species are completely phytophagous, while Ciclocephala species are facultative. The main damage caused by chayote happens because larvae feed on the roots of the plant, reducing water absorption and inducing water stress, which causes the leaves to wither, become chlorotic, and have a rough consistency, while the vine contracts and loses turgor due to the reduction in the absorption of water and nutrients (Figure 10). These organisms do not occur annually since they spend 1–2 years as a larvae in their life cycle. However, when they occur in high populations (Figure 10), their presence is easily noticed by observing the yellowing of the weed, which easily detaches from the ground when holding it. It is generally found in crops where livestock manure fertilizer is applied without composting.

Figure 10.

A: Chayote orchard with dehydration of leaves and vine. B and C: Larva of Phyllophaga sp.

2.1 Macrodactylus mexicanusBurmeister

The adult of this insect is found mainly in corn crops, where it acts as a defoliator. In chayote crops, the larva can cause damage similar to that by the blind man’s hen since it feeds on the plant roots [6], while the adult can cause damage to small fruits and apical buds (Figure 11).

Figure 11.

A: Lesion on the peduncle of a growing fruit, adult puffin (Macrodactylus mexicanus). B: Puffin larva, which differs from the blind hen of the genus Phyllophaga sp., because the raster is smaller and has a smaller number of pallidia.

2.2 Bemicia sp.

The adult measures approximately two millimeters in length, and its body is covered in wax, which gives it a whitish appearance (Figure 12). The nymph is translucent and greenish-yellow; it has four instars, and the first is the only mobile one. From the second instar onwards, it loses mobility, and on the fourth, it stops feeding. It is a widely distributed pest, and it is reported that it attacks more than 500 host plants worldwide, including numerous weeds, vegetables, staples, oilseeds, fruit trees, and ornamentals [7]. To cause direct damage, nymphs, and adults feed by sucking the sap from the leaf. Damaged foliage takes on a mottled, chlorotic appearance and may die. In addition, whiteflies excrete honeydew, where mold-causing fungi establish themselves, covering the leaves and interfering with the photosynthetic process (Figure 12).

Figure 12.

A–C: Whitefly (Bemicia sp.) adults on migrant chayote leaves from alternate crops and weeds near the plantation. B: Honeydew secretion on the leaf. D: Whitefly adults and nymphs on the underside of the leaf with oviposition and development of nymphs.

However, it is considered a pest of great importance in vegetable production because it can transmit viral diseases, generally geminivirus, and due to its ability to survive the application of insecticides, which increases production costs. In chayote orchards where whiteflies have occurred, it is due to the association and intercropping with other crops such as pumpkin and beans or as a result of the shelter provided by the weeds.

2.3 Rhopalosiphum maidis Fitch

Aphids can be found according to the availability of food in wingless and winged forms (Figure 13).

Figure 13.

A–C: Tender shoots highly colonized by wingless aphids on the upper and lower sides of the leaf. B–D: Sooty mold growth on aphid excreta.

Wingless aphids have an elongated body with short antennae and are dark in color, as are their legs. Their cornicles are short (although a little longer than the cauda), completely black, and with a constriction near the apex. The sixth antennal segment with the terminal process (filament) is approximately twice the length of the base. Winged aphids have characteristics similar to those of wingless; they have two pairs of membranous wings, and the pair of anterior wings has three branches in the middle vein. Various species of aphids have been found in chayote crops, with R. maidis being the one most frequently found in cloud forest conditions.

This pest affects chayote when the plant is in full development, since it is favored by high temperatures (March to June). Infestation in the garden begins with small populations; however, given their viviparity condition, the aphids that invade are females that reproduce parthenogenetically, giving rise to more females with the same characteristics.

Detection of this pest in time is important to maintain population levels below the economic threshold of damage. Wingless aphids are found on the underside of the leaves, where they feed by absorbing the sap, which turns yellow and dries. Another occasional damage is the growth of sooty molds, which harbor and develop on the excreta of aphids and other sucking insects (Figure 13B). Aphids establish themselves on the tender tissues of the vine and leaves, so continuous inspection of the plot is of special importance, mainly in areas facing air currents or in neighboring crops.

2.4 Acalymma sp.

Striped beetle adults are about 1 cm long. They have a dark color on the elytra with longitudinal yellow stripes, and their antennae are long and filiform (Figure 14).

Figure 14.

A and B: Striped beetle adults Acalymma sp. in commercial chayote orchards. C: Adult of Acalymma sp. in male inflorescence of chayote.

This beetle can transmit bacteria, and it is attributed to cause damage to expanded and growing leaves. It is normally found feeding on wild and cultivated cucurbit species. In cloud forest conditions, the adults of this beetle appear at the end of April and in more populations during the month of May.

2.5 Eotetranychus lewisi

Female mites (Eotetranychus lewisi) have tarsus I with two pairs of double setae, with three or five tactile setae next to the double silk. They have an empodium divided distally and a hysterotomy with a fourth central dorsal seta in a normal position. In addition, they have two pairs of anal setae and normal striae; the dorsal setae are not on tubercles; they are longer than the intervals between their bases (Figure 15).

Figure 15.

A: Mite (Eotetranychus lewisi) lodging on central veins of chayote leaf. B: Photograph of a permanent preparation showing a male mite under a compound microscope at 16×.

Males show a very narrow hysterotomy; their aedeagus curves ventrally in a sigmoid shape, gradually tapering toward the end. Mites occur between the months of February to July with high temperatures. They are generally found on the underside of the leaves near the veins (Figure 16A and B). They cause damage to fruits, which appear as opaque white-brown “scabs” (Figure 16C and D), reducing the commercial quality of chayote. Part of the damage is the reduction of photosynthetic activity as the leaves acquire an ashy appearance, which accelerates senescence and death. The easiest way to diagnose mites in the plantation is to observe the presence of a spider web near the main veins of the leaf, which serves as protection for the mites and as a means of dispersion when air currents occur (Figure 16A and B).

Figure 16.

A and B: Leaf damage caused by Eotetranychus lewisi. C and D: Damage caused to the fruits.

2.6 Diaphania nitidalis (STOLL)

The adult measures about 2 cm in length by 3 cm of wing expansion, the body is dark brown, and both wings are dark with purple sheen. On the forewings it has an irregular creamy spot and, on the hindwings, approximately two-thirds of the surface is creamy, starting from the base. At the distal end of the abdomen it has a tuft of dark brown scales (Figure 17).

Figure 17.

A: Adult fruit borer (Diaphania nitidalis), forewings with an irregular cream-colored spot, distal end of the abdomen with a tuft of dark brown scales. B and C: Larva boring into the third instar fruit exhibiting conspicuous black spots. D: Last instar larva close to pupation. E: Larva with a black spot next to the cephalic capsule (distinctive character).

The larva is pale yellow or greenish white, except for the head capsule and prothorax, which are brown. At its maximum development, it measures 2–3 cm in length. The first to fourth instar larvae have numerous conspicuous black spots distributed evenly over the body (Figure 17B). The last instar (fifth) does not present such black spots. It has a black spot next to the head capsule (toward the genal angle), and the ocellus II is closer to ocellus I than to ocellus III. The hooks of the prolegs are arranged in a triordinal mesopenellipse (Figure 17D).

Newly hatched D. nitidalis larvae generally feed on the undersides of young leaves. However, in later stages, they cause damage to chayote fruits at any stage of development; in fact, even when they are close to harvesting, one larva per fruit can be found. When the drilled fruits are small, they detach from the plant, while those next to be harvested remain attached (Figure 18A).

Figure 18.

Fruit borer (Diaphania nitidalis). A: Fruit borer egg laid on the underside of the chayote leaf. B: Fruit auger at horticultural maturity. C: Fruits of the S. edule var. virens levis. D: Var. nigrum xalapensis damaged by borer in the field and the excreta of the larva is observed on the epidermis.

The larvae use silk to completely surround the chayote or cover the hole where they entered (Figure 18B–D). When the fruit is drilled, the incidence of diseases causing rot increases.

Drilled chayote fruits are found most abundantly in March to December and are easily identified by the excreta of the larvae attached to the epidermis of the fruit (Figure 18C). The adults are nocturnal, although they can also be found prostrate on the leaves during the day. This stage of development (moths) does not cause direct damage to the chayote fruit. However, it is important to recognize them in order to prevent the outbreak of larvae and to perform pruning in a timely manner. Figure 19 shows fruits wrapped with silk and leaves with masses of eggs that are generally eliminated with the application of pruning, avoiding the use of agrochemicals.

Figure 19.

A and B: Chayote fruits wrapped with silk from the Diaphania nitidalis larva. C and D: Egg masses deposited on leaves of chayote S. edule var. virens levis and var. nigrum xalapensis, respectively.

2.7 Diaphania hyalinata L.

The moth is nocturnal, generally laying its eggs on leaves, tender shoots, vines, or fruits. The eggs can occur singly or in small groups. This borer goes through six larval stages, of which the first and second do not cause significant damage. However, from the third instar, it attacks the vine and enters the fruits, where it develops completely until it reaches its maximum size. The pupa stage develops outside the fruit. Multiple larvae have been observed with a high incidence of D. hyalinata, which cause defoliation and holes in fruits, unlike the attack from D. nitidalis which only presents one larva per fruit (Figure 20).

Figure 20.

A: Diaphania hyalinata moth (adult). B: Chayote fruit var. nigrum spinosum attacked by several larvae.

The head and thorax of adults are brown, the abdomen is whitish, and they display a tuft of long, dark scales on the posterior end. The coloring of the wings is characteristic; both are white, almost transparent; the anterior ones are surrounded by a wide dark brown stripe, except on the anal margin, while that stripe is continuous on the apical margin of the hind wings.

The larva is light green, with two thin white lateral–dorsal longitudinal stripes and the head capsule is yellowish. Ocellus II is much closer to Ocellus I than to III (characteristic of the genus Diaphania). Unlike D. nitidalis, D. hyalinata does not have a black genital spot, and young larvae lack black spots on the body (Figure 20).

The adult moth of D. hyalinata has white, almost transparent wings. The forewings are surrounded by a dark brown stripe, and it also has a tuft of scales on the last abdominal segment. In severe attacks, the larvae destroy the orchard by defoliation (Figure 21).

Figure 21.

Commercial chayote orchards were severely defoliated by Diaphania hyalinata larvae. The incidence of this pest is favored by high temperatures and the permanence of infested fruits in the plot.

As for the affected fruits (Figure 22), it is advisable to eliminate those that fall when pruning the vine to prevent the moth from completing its development.

Figure 22.

A and B: Diaphania hyalinata larvae feeding on chayote leaves. C and D: Chayote fruits at horticultural (commercial) maturity severely damaged by D. hyalinata.

Field studies for the identification and control of pest organisms in chayote are permanent, and this knowledge increases each year. The purpose is to have the highest number of organisms identified, to know the time when they occur, the type of damage they cause, as well as the control methods that are friendly to the environment, the field worker, and the consumer.

The activity of pruning the vertical and horizontal vines helps reduce maintenance costs due to excess vine in the canopy; it levels the weight in the support structure and helps avoid fractures; it allows more light to enter and prevents decoloring of the fruits while maintaining their quality (Figure 23); but, above all, it eliminates many pest organisms that cause serious disorders and avoids the application of agrochemicals. Pruning in commercial chayote orchards is a practice for ecological or organic production and a responsibility to the environment and the people involved in this activity and consumption. Research continues to determine more precisely the economic thresholds of damage and the use of alternative products for pest control [8, 9, 10].

Figure 23.

Commercial fruits of chayote var. virens levis discolored due to the effect of attached senescent leaves and less light entry because of excess vine in the canopy.

3. What is being done?

Biological control involves the use of natural enemies to reduce pest populations, either temporarily or permanently. In some cases, natural enemy populations are manipulated to cause a permanent change in the food web surrounding the pest. Some biological control approaches are designed to reinforce the densities of natural enemies by improving their living conditions. Three biological control methods that are being implemented are described below.

3.1 Biological control for conservation

It is the study and manipulation of natural enemies so that they suppress pests. The objective is to minimize the factors that detrimentally affect beneficial species and reinforce those that make agricultural fields a suitable habitat for natural enemies. This approach assumes that natural enemies already present can potentially suppress the pest if they have the conditions to do so. This assumption is likely for many native insect species but not for weeds or invasive insects.

3.2 Biological control by introduction

If there are no natural enemies that effectively control the pest, then the introduction and permanent establishment of new species can be considered. This form of control, also called classic biological control, is most frequently used to control exotic pests, which commonly arrive in a new area without natural control factors. When used to control native pests that lack effective natural enemies, it is called “neoclassical biological control” or “new association classical biological control.” In successful cases, this form of control can reduce pest levels indefinitely to levels below economic thresholds.

3.3 Biological control by increase

When natural enemies are biologically effective but fail to control pests despite conservation or introduction efforts, population growth can be achieved through mass breeding and inoculum release (of the biological control agent, which multiplies and controls the pest for a certain time) or flooding (control is carried out exclusively by the released individuals). Because this form of biological control can be more expensive than the others, it should only be used if other forms of biological control are inefficient. In naturally productive areas of chayote, there are organisms that serve as biological control agents, among which members of the Coccinelidae, Chrysomelidae, Pelecinidae, and Rediviidae families stand out, which exert control over populations of aphids, thrips, and other pests. Below are some examples (Figures 24-26).

Figure 24.

Adults of the genus Partamona sp. on staminate flowers, trumpet-shaped nest entrance.

Figure 25.

A: Coccinellid feeding on aphids. B: Cycloneda munda adult feeding on thrips on male chayote inflorescence.

Figure 26.

A: Pelecinus politurator parasitoid in chayote orchards; they are parasitoids of blind hens, and the adults emerge at the end of summer. B: Lacewing prostrate on a chayote leaf, green body, and wings with a large number of veins, and they feed on whiteflies, aphids, thrips, larvae of Coleoptera, Lepidoptera and mites.

Technical advisors and producers are also undergoing professionalization in the use of control organisms, such as Bacillus subtilis, via foliar application, which acts as a biological fungicide-bactericide with preventive action recommended for the control or suppression of various diseases. Likewise, the application of Bacillus thuringiensis against immature stages of lepidopterans is effective, since its toxin produces strong havoc within the larva when ingested, causing death due to starvation, in addition to Trichoderma harzianum.

4. Future perspectives

Chayote production represents an economically important value network for different regions in Mexico, Central America, and the Caribbean. It represents a local source of rural employment. The nutritional and nutraceutical value of chayote as a vegetable has increased consumption and, therefore, truly important actions to take are identifying the pest organisms that limit its production and designing control strategies that are friendly to the environment and the consumer’s health. This includes favoring the reduction of the use of agrochemicals of synthetic origin in the cultivation fields. This study represents the first systematic study carried out in the field to identify pest organisms in chayote, with the aim of providing a guide to technicians, producers, and researchers, and facilitating the processes of national and international certification for exporters. The actions of identification, classification, and alternative control of pest organisms, in addition to their benefits as antagonists, pollinators, and natural control, represent a permanent program with the aim of reducing the environmental impoverishment of production areas as a result of the mistaken use of toxicological groups which consider all insects as damaging to chayote.

5. Conclusions

This study is an approach to the pest organisms that are currently causing decreases in the productivity of the S. edule crop. The importance of its dissemination is that users in the world where this species is cultivated can identify the pests and adopt pruning as a control practice. Our research group continues working in the field to identify new pest organisms that affect chayote productivity, in addition to improving control practices so that the final product is reliable for consumption.