Savigny's grasshopper

Savigny's grasshopper (Aiolopus savignyi) belongs to the order Orthoptera and the family Acrididae (true locusts). This insect is medium-sized and possesses a strong ability to jump and fly, which makes monitoring its movement across fields quite challenging.

The adult insect typically displays protective coloration, ranging from grayish to brownish tones, allowing it to blend effectively into the background of dry soil or sparse vegetation. A distinctive feature is the structure of the hind legs, which are adapted for making powerful leaps when the insect feels threatened.

Larval stages resemble smaller, wingless versions of the adults. Through several instars, the nymphs gradually increase in size and acquire the morphological features of the adults, including the specific venation patterns on the forewings.

The sensory organs of the pest, including its complex compound eyes and sensitive antennae, allow it to locate favorable spots for oviposition successfully. Females are equipped with a developed ovipositor, which enables them to deposit egg pods deep into the soil layers to protect them from environmental fluctuations.

This species prefers open, well-sunlit areas. In agricultural ecosystems, these spots often include field margins, roadsides, and uncultivated strips, where the microclimate is optimal for population proliferation.

Savigny's grasshopper is a polyphagous insect, meaning it has a wide range of host plants. In agricultural settings, this pest poses a significant threat to various field and fodder crops, feeding on both wild grasses and cultivated plants alike.

The primary damage is inflicted upon cereal crops such as wheat, barley, and millet. The pest actively feeds on leaf blades, which reduces the photosynthetic surface area and, consequently, leads to significant yield losses in grain production.

Beyond cereals, the grasshopper threatens forage crops, including various types of alfalfa and clover. Mass outbreaks of these insects in pastures can lead to a substantial reduction in the biomass available for hay production or livestock grazing.

During periods of high population density, the pest may switch to vegetable crops located near hatching sites. Damage to the vegetative organs of young plants often results in their total destruction or significant stunting of their development.

The harmfulness of this grasshopper increases during drought years, when natural vegetation dries out, forcing the insects to concentrate on succulent irrigated or late-season crops, inflicting catastrophic damage upon them.

The lifecycle of Savigny's grasshopper is inextricably linked to seasonal temperature regimes. The pest mainly overwinters in the egg stage; females deposit their eggs in compact groups within dense soil pods, which are protected by glandular secretions.

In spring, once consistent positive temperatures and adequate humidity are reached, nymph hatching begins. This process is usually stretched over time, which complicates the timing of pest control measures in the field.

Nymphal development proceeds through 5 instars, accompanied by molting. During this period, the insects feed actively, gradually increasing the volume of plant material consumed, which makes them particularly dangerous to young crop sprouts.

The transformation into an adult occurs in mid-summer. Adults are highly mobile and capable of migrating over significant distances in search of suitable feeding grounds, which expands the potential zone of infestation.

By late summer or early autumn, mating and egg-laying in the soil take place. After completing the oviposition cycle, the life cycle of the adults ends, and the population enters diapause until the following spring season.

The first sign of the pest's presence is the occurrence of characteristically gnawed leaf edges. Often, the damage appears as irregular jagged cuts that start from the leaf margins and gradually move toward the central vein.

The presence of grasshoppers is easy to detect during visual inspection of crops in sunny weather. When a person approaches, adult insects make sudden, sharp jumps, creating noticeable movement within the canopy.

In fields with high pest density, bare patches may appear where vegetation is severely thinned or destroyed down to the stubble. This is especially visible at the edges of fields bordering fallow or weedy areas.

In areas where nymphs congregate, exuviae (shed skins) can be found after molting; these remain on plant stems or on the soil surface. This is a crucial indicator of active population growth and the approach of the next developmental stage.

An indirect sign of infestation is the activity of insectivorous birds in the field, which begin to concentrate in areas of mass grasshopper outbreaks to utilize them as a food source.

The primary control method is an agronomic approach aimed at creating unfavorable conditions for pest development. The most critical factor is timely soil tillage, including deep plowing, which destroys the soil pods containing the eggs.

An effective measure is the destruction of weeds along field margins and roadsides, as these areas serve as primary reservoirs for grasshopper hatching. Maintaining cleanliness in fallow fields significantly reduces the likelihood of population explosion.

Upon reaching the economic threshold of damage, the application of contact-stomach insecticides is necessary. It is crucial to perform treatments during early morning or evening hours, when the pests are less mobile and the effectiveness of the preparations is maximized.

Biological control methods include the use of entomopathogenic fungi or the release of natural enemies, such as predatory insects, provided that the ecological balance of the agroecosystem has not been disrupted by excessive pesticide use.

• Monitoring population density using trap plots.
• Following crop rotation schemes to prevent pest accumulation.
• Using selective insecticides to conserve beneficial entomofauna.