BLIND HEN: CHARACTERISTICS, LIFE CYCLE, NUTRITION, CONTROLS - BIOLOGY - 2025

The blind hen is the name given to the larvae of several species of beetles of the genus Phyllophaga. Adults, meanwhile, are given names such as drone of May, chicote and mayate, among several others. These organisms are herbivores and their larvae can become a pest of crops, being one of the most important pests in America.

Phyllophaga beetles have a life cycle with complete metamorphosis and lasts approximately one year. Females lay 60 to 75 eggs that must pass through three larval stages and a pupal stage before reaching adulthood. These larvae are very voracious and must eat about 80% of their weight daily.

Representative larva of beetles of the Scarabaeidae family. Taken and edited from: Whitney Cranshaw, Colorado State University, Bugwood.org.

The blind man's diet is based on plant roots, which suddenly begin to dry out for no apparent reason. It is a pest that attacks a wide variety of crops, mainly corn, potatoes, wheat, tomatoes, fruit trees and grasslands, with estimated damage in some cases greater than 80% of the planting.

The mechanisms of control and eradication of the blind fowl include the use of chemicals, some of which are very toxic. Different natural enemies of these larvae have also been used as biological control, mainly nematodes.

General characteristics

Phyllophaga lanceolata adult. Taken and edited from: xpda.

Blind chickens are the larvae of a group of species of beetles in the family Scarabaeidae, all belonging to the genus Phyllophaga. These organisms go through three larval stages and one pupal stage before reaching adulthood. Although they always feed on plants, the main damage to crops is caused by larvae.

Egg

Its shape varies as embryonic development progresses, being initially elongated, with a diameter greater than 2 to 2.1 mm and a diameter less than 1.5 millimeters approximately. Then it acquires a more spherical shape.

Larvae

They are worm-shaped and have a well-developed head, strong and prominent jaws, three pairs of pseudo-legs that they use to move, and at hatching they are approximately 8 mm in size.

They have a coloration that can be whitish, grayish or yellowish, with the cephalic region of dark brown to black color and spiracles (breathing holes) of brown color, located on both sides of the body.

They have three larval stages. The first of which lasts approximately 25 days, during which time the larvae triple in size and undergo some changes, including strong development of the jaws and chewing muscles. By the time the larva is about to pupate, it has reached 4 cm in length.

Pupa

The pupa has a shape similar to that of the adult and a brown color. It develops enclosed in a pupal chamber that is oval in shape and comparatively large in size. It is generally buried at a depth ranging between 30 and 60 cm.

Adult

Adults can reach up to 4 cm depending on the species and their color is generally blackish to reddish brown. It does not present conspicuous spots. The adult forms of the different species are very similar to each other, which is why a detailed study of the male genitalia is necessary to differentiate them. In the following video you can see the larvae:

Lifecycle

The life cycle of the blind hen lasts between one and two years depending on the species. The reproductive cycle begins with the rainy season. After copulation, the female can deposit up to 75 eggs, which she encloses in balls of clay under the ground.

The incubation time depends on the temperature and generally lasts between two and a half weeks and three weeks, although in some species it can last only a week. Then the larvae hatch, which move with their three pairs of pseudo legs to feed. Several days before each molt the larvae stop feeding.

The larvae go through three stages, each of which lasts longer than the previous. The first larval stage lasts approximately 25 days. The second has an average duration of 35 days, although it can last up to 50 days, while the third stage can last up to 9 months.

The molting of the third larva leads to a pupal phase, which builds a pupal chamber where it remains inactive for a period that can last from one to three months before emerging as an adult.

The adults are nocturnal, feed on leaves and copulate during the rainy months to start a new cycle.

Nutrition

Not all blind hens are herbivores, and among the latter, not all cause significant damage to plants. The larvae of some species feed on plant debris or on soils with abundant organic matter.

Other species can optionally feed on live plants if they do not find plant remains. Only a few species feed exclusively on live roots. The adults feed mainly on leaves, which gives rise to the genus name (Phyllophaga) which literally means leaf eater, they can also consume flowers.

For blind hens to become a pest, they must be in sufficient numbers to be able to cause damage to a significant number of plants, which can happen on some occasions, and in those cases they can cause losses of more than 80% of the estimated harvest.

Blind chickens feed on a huge variety of plants, among which we can mention grasses such as corn, sorghum and wheat, potatoes, tomatoes and various fruit species. They represent one of the main agricultural pests in America.

However, blind hens help the circulation of water and air between the roots, benefiting the soil just like earthworms. Additionally, they help in the food cycle, by accelerating the transformation of large remains into smaller substances, more easily assimilated by other smaller organisms.

Blind chicken control

Phyllophaga sp. Taken and edited from: Patrick Coin (Patrick Coin).

These beetles have a wide latitudinal distribution in the American continent, inhabiting from the United States to Argentina and at altitude their distribution is also wide, even at 3,500 meters above sea level.

Managing blind hen populations to avoid damage to plantations includes not only the application of chemical pesticides, but also the use of biological controllers and cultural practices.

Due to the harmful effects of chemical agents and their permanence in the soil, some authors suggest using this type of substances only when the concentrations of beetles or their larvae are high and exceed an economic threshold.

This threshold varies depending on the author, the species of beetle involved, the type of culture, among other variables, but generally a threshold is established that is between 4 and 12 Phyllophaga larvae in stage three.

Among cultural practices, fallow and ground tracking serve to prepare it, but they also help to eliminate larvae and pupae, not only due to the mechanical action of the tillage implements, but also because the exposed insects are susceptible to desiccation. and to be preyed upon by birds and other organisms.

Another growing practice is the use of artificial light during night hours to attract and eliminate adults before they reproduce.

Chemical control

If, after cultural management, the densities of the larvae continue to be higher than the economic threshold, the use of chemical agents is suggested to control the pest. There is a wide variety of products that can be used for this purpose, including non-fumigant nematicides.

Among these types of products are terbufos, ethoproph, phorate and chlorpyrifos, which have shown that in addition to controlling nematode populations, they also do so with blind hens, without affecting single-celled organisms that can be beneficial to plants.

Insecticides are not always efficient in eradicating the pest and sometimes the yields of plots not treated with these products is similar to that of plots if fumigated.

Several of the products that have shown better results in the control of blind fowl have high toxicity and residuality, which is why their use has been prohibited in some countries, such as carbofuran and phosphorodithioate, prohibited in Mexico.

Biologic control

Biological control refers to the use of natural enemies of an organism in order to control or eliminate its populations. Blind hen has numerous natural enemies, including entomopathogenic fungi and nematodes, flies of the Pyrgotidae family and wasps of the Pelecinidae, Scoliidae and Tiphiidae families.

The main efforts to control this larvae have been carried out using fungi of the Metarhizium anisopliae species.

On the other hand, among the nematodes used against blind fowl are those of the Steinernema glaseri species, Heterorhabditis bacteriophora. Heterorhabditis sp., Beauveria bassiana and B. brongniartii.

Both fungi and nematodes have been used individually or in combination with each other, with variable results, but generally satisfactory in controlling the pest.

References

1. Phyllophoga. On Wikipedia. Recovered from: en.wikipedia.org.
2. S. Girón-Pablo, J. Ruiz-Vega, R. Pérez-Pacheco, T. Aquino-Bolaños & L. Martínez-Martínez (2015). Biological control of Phyllophaga vetula (Horn) with entomopathogenic nematodes in various formulations and moisture conditions. Southwestern Entomologist.
3. Blind chicken: what is it and how to eliminate it? Recovered from jardineros.mx
4. AA García, M.Á. Morón, JF López-Olguín & LM Cervantes-Peredo (2005). Life cycle and behavior of adults of five species of Phyllophaga Harris, 1827 (Coleoptera: Melolonthidae; Melolonthinae). Acta zoológica mexicana
5. P. Grewal & R. Georgis (1998). Entomopathogenic nematodes. In: FR Hall & JJ Menn, Methods in Biotechnology. Vol. 5. Biopesticides: Use and Delivery. Humana Press, Totowa, NJ.
6. M.Á. Morón, CV Rojas-Gómez & R. Arce-Pérez (2016). The role of the "blind chicken" in grasslands Biodiversity and Systematic Network. Inecol.