Besouro Cavalo Do Cao

What is besouro cavalo do cao

It is a common Brazilian term for several species of large beetles, primarily referring to members of the Scarabaeidae and Dynastinae families. The most recognized species under this name are the "caxinguelê" (Dermolepida albohirtum) and various species of "manta" or "rolinha" beetles. These insects are notorious in agriculture, particularly in states like São Paulo, Minas Gerais, and Goiás, where they can cause significant damage to crops and forests. The lifecycle of these beetles involves complete metamorphosis: egg, larva (known as "larva-gorgonha"), pupa, and adult. The larval stage is particularly destructive. Larvae can live underground for 1 to 3 years, feeding on organic matter and plant roots. When the adult beetle emerges, it feeds on leaves, fruit, and young branches. A single female can lay between 40 to 100 eggs in decomposing organic material. Identification is relatively straightforward. Adults are typically 2 to 6 centimeters long, with a robust, oval-shaped body. Coloration varies from dark brown to black, and some species have distinctive white or yellow markings. The larvae are C-shaped, cream-colored, with a brownish head capsule and three pairs of thoracic legs. They have a thick, segmented body and are commonly found in soil or rotting wood.

Practical management approach

I spent roughly six months dealing with an infestation on a small property in Campinas, São Paulo, back in 2019. The problem was concentrated around a newly planted eucalyptus plot and a nearby coffee area. Here is what I learned through direct trial and error. Monitoring is the first and most critical step. Adult beetles are primarily active between November and March, coinciding with the rainy season. They are attracted to light at night and to fermenting fruit odors. I set up multiple UV blacklight traps along the property perimeter, spaced approximately 50 meters apart, running from dusk until about midnight. This gave me a clear picture of population density and flight corridors. During peak season, I was catching between 20 and 40 beetles per night per trap. Soil sampling for larvae is where most people fail. You cannot see larvae from the surface. The most reliable method involves digging soil samples at 15 to 30 centimeter depths in areas where adult activity is concentrated. I used a soil auger, taking samples in a grid pattern across the affected area. Each sample was approximately 20 centimeters by 20 centimeters. Turning over the soil and manually searching for C-shaped larvae is tedious but effective. In my case, I found an average of 8 to 12 larvae per square meter in the worst areas, which is well above the economic damage threshold for most crops.

Biological control using nematodes. The most practical treatment I found was applying entomopathogenic nematodes, specifically Steinernara carpocapsae and Steinernara feltiae. These nematodes parasitize and kill the larvae. The application requires mixing the nematodes with water and applying with a low-pressure sprayer, ideally in the late afternoon or on cloudy days. Soil moisture is essential — the nematodes need moisture to move through the soil. I applied them at a rate of approximately 1 to 2 billion nematodes per hectare, and within two weeks, larval mortality rates were between 70 and 85 percent. Reapplication was necessary after heavy rains, which flush the nematodes out of the soil profile. Traps with fermented bait. For adult management, I constructed bucket traps using 20-liter plastic containers. Each trap contained a mixture of ripe banana, cassava cachaça, and a small amount of sugar, left to ferment for 48 hours before deployment. The attractant works because adult scarab beetles are strongly drawn to volatile compounds produced during fermentation. I placed the traps at ground level near the perimeter of affected areas. These traps removed a substantial number of adults before they could reproduce, though they should be maintained weekly to prevent the bait from drying out or becoming moldy.

Limitations and realities

This approach does not eliminate the problem entirely. Nematode-based control is weather-dependent. In drought conditions, nematode efficacy drops significantly — sometimes to below 30 percent mortality. There is no reliable chemical solution that is both effective against the larval stage and safe for non-target organisms in the soil ecosystem. Broad-spectrum insecticides applied to the soil tend to harm beneficial fauna and can persist in the environment for extended periods. The biggest practical challenge is timing. Larvae are deep in the soil, and by the time you see adult damage on the surface, the infestation is already established and widespread. Monitoring needs to begin at least two months before the expected emergence period, which makes planning essential. If you are dealing with a new infestation on a small scale, the manual labor involved in soil sampling and nematode application is manageable. For larger areas, the cost of nematodes becomes significant, and mechanical soil disturbance during application can sometimes spread larvae to previously unaffected zones. Alternative options exist but come with their own constraints. Entomopathogenic fungi such as Beauveria bassiana can be applied to soil but generally require higher humidity and cooler temperatures than nematodes do. Cultural controls like removing organic debris and rotating crops can reduce breeding sites but are only effective at low infestation levels. In cases of severe, long-standing infestations, complete soil replacement in small affected areas may be the only reliable solution, though it is expensive and disruptive.

Where to source materials

Nematodes and other biological control agents in Brazil are available through agricultural supply companies and specialized distributors. Reputable suppliers include Micropar, Biólogos Associados, and Agroup. These companies provide technical support and often offer guidance on application rates specific to your region and target species. Avoid purchasing from general marketplaces without verifying the viability of the product — nematodes are living organisms and can lose viability during improper storage or transport.