The 6th CEIP student body Sant Isidre de València has participated in a pioneering project coordinated from the Plant Health Service of the Department of Agriculture, which consisted of the breeding of Rodolia cardinalis ladybugs in the school center to release them in the Botanical Garden of the University of Valencia. The objective: to help fight the plague of the ridged cochineal, Icerya purchasi. We tell you about the experience in the following article.
The fluted cochineal, Icerya purchasi, is a very common pest that causes serious problems in both ornamental and citrus plants. It weakens the trees, since it sucks the sap, and secretes a large amount of molasses that reduces the photosynthetic surface of the leaves. Also, this sugary molasses attracts ants (which are capable of acting as cochineal protectors) and facilitates the multiplication of different fungi.
The collateral damage that further aggravates the effects of the pest, which has very heterogeneous populations, with several annual generations and where it is difficult to establish the moments of egg-laying. The mealybug affects the trunk, branches, and leaves, and if the attack is very strong, the tree can die. It is, therefore, a threat that must be faced. And with an army of ladybugs, it is possible.
Flood with Rodolia cardinalis: the biological fight
The biological fight, in which populations of natural enemies are used to reduce the population of a plague species, has been revealed as very effective as a control strategy in some cases. The Regional Ministry of Agriculture of the Generalitat Valenciana has, in fact, different insectaries where species are raised for use in different types of biological control of pests: conservation, classical, inoculative and flooding.
In the case of the fluted cochineal, Icerya purchasi, the biological flood control through Rodolia cardinalis, the ladybugs we know, has been proven as a successful formula. Thus, after raising the sufficient number of the predator, of the ladybugs, they are released in a very high number in the fields affected by the fluted cochineal. It avoids, therefore, the application of phytosanitary products and allows to be more respectful of the environment.
Rodolia cardinalis is a beetle, similar to the ladybird with 7 points, but smaller and with spots instead of points. Both larvae and adults have a very intense predatory activity, on eggs and adults. Ladybug females lay eggs near the ovisac of the cochineal and their larvae feed on the eggs and nymphs of the cochineal.
However, it should not be forgotten that the release must be done at a time of cochineal reproduction, since if the dams are scarce, the fertility of the ladybugs decreases and the cannibalism increases. And reintroduce the insect in the spring or early summer, since Rodolia can not stand low temperatures. Also, it will be necessary to look carefully, if appropriate, what phytosanitary treatments are applied so as not to affect our ally and impair its beneficial action.
The CEIP Sant Isidre lands an army of ladybugs in the Botànic
For the second year, the students of the 6th year of the CEIP Sant Isidre de València have participated in a pioneering project in which, together with the Ministry, they are responsible for the breeding of specimens of ladybugs and the release on trees affected by cochineal from the Jardí Botànic of the University of Valencia.
With this experience, the most important thing has not been to win the battle, but the students of the center have had the opportunity to learn about organic farming and alternative ways to use phytosanitary products to combat pests, more respectful with the environment. Also, they have been able to deepen concepts such as the functioning of ecosystems, biological cycles, the food chain or the balance of nature.