The brown locust, Locustana pardalina, is a medium-sized small locust

Locust

Locusts are the swarming phase of short-horned grasshoppers of the family Acrididae. These are species that can breed rapidly under suitable conditions and subsequently become gregarious and migratory...

 species found in Southern Africa

Southern Africa

Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...

 and shows classic gregarious behaviour with phase polymorphism

Polymorphism (biology)

Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...

) on crowding.

Biology

"With its drought-resistant egg stage, short life cycle with 2–4 generations per year, high fecundity and highly gregarious behaviour, the brown locust regularly produces intense outbreaks. Eggs are usually laid in dry soil and during the summer months will hatch approximately 10 days after 15–25 mm (0.590551181102362–0.984251968503937 ) of rain has fallen. Under drought conditions, eggs enter various states of diapause and quiescence and can remain viable for up to 3 years.

Incipient outbreaks generally arise following the end of droughts and are characterised by the dramatic increase in the density of the solitary phase adult population over wide areas of the Karoo. Hatching hoppers then aggregate and develop into thousands of small, discrete, highly gregarious hopper bands. For example, over 250,000 hopper bands and 40,000 fledging adult swarms were controlled in the massive 1985–86 upsurge. Swarming populations can then perpetuate themselves for a number of years, requiring an intense control effort, before gradually dying out during another drought cycle."

Control

Hopper band outbreaks are frequent in the Karoo

Karoo

The Karoo is a semi-desert region of South Africa. It has two main sub-regions - the Great Karoo in the north and the Little Karoo in the south. The 'High' Karoo is one of the distinct physiographic provinces of the larger South African Platform division.-Great Karoo:The Great Karoo has an area of...

 and are controlled by farmers with insecticide

Insecticide

An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...

 spray operations: usually deltamethrin

Deltamethrin

Deltamethrin is a pyrethroid ester insecticide.-Usage:Deltamethrin products are among the most popular and widely used insecticides in the world and have become very popular with pest control operators and individuals in the United States in the past five years. This material is a member of one of...

 with motorised mistblowers set for ultra-low volume

Ultra-low volume

The term Ultra-Low Volume is used in the context of pesticide application.Ultra-low volume application of pesticides has been defined as spraying at a of les than 5 L/ha for field crops or les than 50 L/ha for tree/bush crops...

 application (subsidised by the Government).

Because of the environmental sensitivity of the Karoo biome

Biome

Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a...

 and concerns about toxicity to grazing sheep, a biological pesticide product called 'Green Muscle', based on the entomopathogenic fungus

Entomopathogenic fungus

An entomopathogenic fungus is a fungus that can act as a parasite of insects and kills or seriously disables them.-Typical life cycle:These fungi usually attach to the external body surface of insects in the form of microscopic spores...

 (Metarhizium acridum

Metarhizium acridum

Metarhizium acridum is the new name given to a group of fungal isolates that are known to be virulent and specific to Acrididea. Previously, this species has had variety status in Metarhizium anisopliae and before that, reference was made to M. flavoviride.- Biology :M...

), was tested by the LUBILOSA

LUBILOSA

LUBILOSA was the name of a research programme that aimed at developing a biological alternative to the chemical control of locusts. This name is an acronym of the French title of the programme: Lutte Biologique contre les Locustes et les Sauteriaux...

Programme in collaboration with the South African Plant Protection Institute: using novel application technique to compensate for the slow speed of kill.