Adapt and combine: keys in biological control programs
The distribution of the species of Diatraea In the Cauca River Valley, it confirms the importance of using the entire complex of available natural enemies preventively.
When in 2013 the discovery of two new species of Diatraea (D. tabernella y D. busckella) in the Cauca river valley, Cenicaña began to determine their distribution in the region. By 2016 it was established that:
- Populations of D. tabernella y D. busckella they have not been restricted to the original detection sites and are beginning to move: D. tabernella advances from the north towards the central zone and D. busckella, from the center to the south and north areas.
- In the southern zone, the record of high populations of D. saccharalis that interact with D. indigenella.
- The natural enemies with the greatest attack action in the larval stage of the pest have been the tachyinid flies Lydella minense y Genea Jaynesi; and to a lesser degree the fly Billaea claripalpis and the wasp Cotesia flavipes, the latter recently adapted to the region.
- Established populations of Cotesia flavipes, product of liberation works in the north zone. These populations in the northern zone have caused 15% of parasitism on D. tabernella and 13% parasitism on D. busckella.
Germán Vargas, entomologist from Cenicaña, explains that this situation shows the importance of combining natural enemies in biological control programs to obtain better results.
"It is not about using only the most efficient or the most economical, but about combining those that are available, in such a way that they can protect us from the different species of DiatraeaWell, it is a mistake to think that tabernella is from the north or busckella, from the center, and not prepare with controllers for all species ”, he points out.
For this reason, it is important to facilitate the adaptation of different natural enemies, so that when they are necessary they already exist in the area as an additional management actor. A good example is that of Cotesia flavipes that has become an option to combine with the flies and face D. tabernella.
"To do control over Diatraea we release tachyinids and Trichogramma exiguum, but as a result of the alert that was generated in the north of the Valley, we began to work preventively with Cotesia flavipes. This year we started with releases of half a gram per hectare and we are now going one gram per hectare; in addition, we are venturing into the breeding of Cotesia at the laboratory".
Work planning, scheduling and control team leader. Ingenio María Luisa