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    Marine microorganisms, new biopesticide against pasture bugs

The result of a project carried out by two Universidad Nacional de Colombia (UNal) research groups established that 2 out of 250 microorganisms coming from algae, octocorals, sponges and inclusively from sea-bed sediment from near the Colombian city of Santa Marta, the Rosario Islands and the Island of Providencia, have great potential to control pasture bugs (Collaria scenic).

This bug is an insect capable of sucking the sap of Kikuyu grass (common cold weather grass) with a mouth that has a mechanism similar to a needle allowing it to penetrate the grass surface and drying out the grass, causing great losses to small and medium-sized milk farmers. This situation has led researchers to work on a project to implement good soil improvement practices, besides mixing pastures with oat, clovers and other types of foraging materials.

However, since Kikuyu grass develops better than other species at heights between 1,000 and 2,000 meters above sea level, (3,280 – 6,5560ft.) it is essential to have a product capable of controlling pasture bugs, which have now developed resistance against conventional pesticides and also cause abortions in cattle.

The bugs range between 2 and 5mm. and with an estimated life-cycle between 40 to 45 days in which the insect lacks wings; another suggestion for control is to change pasturing cycles and attack the bug before it reaches adulthood.

Since Kikuyu grass develops better than other species at heights between 1,000 and 2,000 meters above sea level, (3,280 - 6,5560ft.) it is essential to have a product capable of controlling pasture bugs.

Flying makes controlling the bug much harder, plus the fact that after 90 days it begins to lay eggs close to the ground, an area which results inaccessible for any type of insecticide. Therefore Professor Nubia Moreno of the Biotechnology Research Institute (IBUN, for its Spanish acronym) suggests applying pesticides eight days before pasturing and before 40 days.

Response comes from the sea

A UNal Department of Chemistry research group known as “Research and use of marine natural products and fruits in Colombia” provided a collection of 250 microorganisms for experts of the Bioprocesses and Bioprospection Research Group to carry out studies to determine their possible use as biological controllers for the agricultural sector. The former has experience in identifying compounds responsible for biological activity, and the latter has experience in large-scale cropping and production.  Their combined work was instrumental in these findings.

The work of Department of Chemistry Professors Leonardo Castellanos and Freddy Alejandro Ramos, established that 2 of the 250 microorganisms analyzed had the potential to control the pasture bug.

“Stemming from a set of studies and statistical analyses in experimental conditions, we were able to establish that the microorganisms used would not harm the grass and could effectively control the insect,” said Ramos. They also verified that cattle would continue regular grass consumption after adding the microorganisms to the grass.

The researchers analyzed 80 strains in aspects related to taxonomic features, chemical production and easiness of cropping but also dismissed strains which could potentially be pathogenic and cause harm to cattle.

“We carried out biological activity tests in greenhouses with all the available microorganisms, introducing them into the diet of Collaria to assess its behavior, until coming to the conclusion that two microorganisms from the Paenibacillus genus had the potential to be used in the field, could withstand different environmental conditions and also reproduce rapidly,” said Moreno

They analyzed 80 strains in aspect related to taxonomic features, chemical production and easiness of cropping but also dismissed strains which could potentially de pathogenic and cause harm to cattle.

From the sea to the fields

These microorganisms have the capability of forming spores and after being applied on the grass they leave the latency status and develop their activity as if they were in their place of origin.

These types of microorganism may be found both on land as in the sea; therefore it is possible to find the same species in other areas, although with different metabolism which could be more or less effective.

After this potential has been verified, the researchers will carry out a production process in cultures which offer the best nutritional, temperature, and acidity conditions, as well as oxygen levels among others.

“In order to guarantee the best growth conditions, we have a source of carbon – saccharose, starch or oat–, nitrogen, vitamins, and minerals, from a series of detailed studies carried out by the Institute,” said Moreno.

Once they have the sufficient amount of microorganisms the researchers will develop a type of formulation to protect them until they are introduced into the field.

After almost a year, they have carried out several tests in different areas of Ubaté (Province of Cundinamarca) with the purpose of establishing the behavior in real field conditions, as opposed to laboratory conditions, the microorganism will now be exposed to environmental dynamics like sun and rain and an eventual depletion of nutrients.

After this stage is done, they can establish the behavior of the biocontrollers which up to now have a 70% success rate in laboratory conditions and with the purpose of teaching farmers the best way of using them to control pasture bugs. The effectiveness goal is for the bug not to develop resistance to the product.