Habits and damages caused by Mocis latipes in grassland ecosystems

As for the habits of the insect, it can be said that it tends to proliferate on the surfaces intended for grazing in a sporadic and explosive way, since the arthropod according to some researchers does not proliferate in periods of water deficit and also when the rains increase, that is to say there must be a balance between temperature and soil humidity, that is why in tropical areas with intermittent rains this type of insects can be observed, as it happens in the paddocks of the Municipality Colón State Zulia where they have been detected in the months of June and December, when the rainfall is intermittent.

On the other hand, when the eggs hatch, the larvae appear that in their first instars cause scrapes on the tender parts of the leaves, presenting as small translucent areas, because they only leave the lower cuticle of the leaves almost intact, in the same way as the larvae are developing they begin to cause greater damage to the leaves, since it is observed as a kind of cutting or perforations in the leaf blade, sometimes leaving only the central rib of the blade is not checked in time.

To talk about the damage that larvae can cause, the different instars mentioned by Álvarez and Sánchez (n.d.) will be taken into account, it is their experimental trial and they coincide with what was observed in the field when the different inspections or diagnosis are carried out. The instars of the larvae and the damage they cause as they reach maturity before reaching their pupal stage are mentioned below:

1ST, 2ND and 3RD Instar:the present instars have an approximate duration of 8 days (2,3,3 days consecutively), during this period the small larvae begin to feed on the host plant, they tend to perform a kind of scraping of the leaves leaving translucent areas, because they only leave the lower cuticle of the leaves almost intact.

4th, 5th and 6th Instar:one way to know if the larvae have already passed the 3rd instar when diagnoses are made, is to take the larva and check if they have two transverse dark-colored spots on the back very similar to the Spodoptera, when they are in these instars they begin to defoliate the leaves until they leave the central rib if not controlled in a timely manner, a lava in the last well-developed instar can reach a length of approximately 5 cm. On the other hand, it should be noted that the present instars 4,5 and 6 have a duration of approximately 10 days (4,2,4 respectively).

During all the deliveries that have been made about pest insects in tropical grasslands, it has been recommended that, the first thing that should be done is an inspection on the surfaces cultivated with grasses, since experience teaches that the control of a pest is based on a complete evaluation of it, carrying out field reviews that allow to identify the type of pest, determining if we are in front of a sucking or chewing insect, in that way we can conduct a deep investigation on the biological cycle, in addition to the phases and times when it causes damage, this will allow determining an appropriate time for its control, in addition to planning the most appropriate control method.

In the case of Mocis latipes, when you have susceptible grass species and you have a history of attacks by said insects in neighboring areas, it is recommended that the paddocks be monitored frequently, especially if there are changes in climatic conditions, specifically when precipitation occurs, since humidity will increase and coupled with high temperatures of the tropical zones the ideal conditions for the proliferation of the arthropod are created..

Currently microbiological control methods are widely used, for preventive control it is recommended to apply Bacillus thuringiensis (wettable powder) at a rate of 0.5 - 0.75 kg /ha mixed with enough water at the beginning and at the end of the rains, it can also be applied when larvae with very little development are observed, that is, in their first instars, the application should be carried out evenly on the foliage of grass and arvenses , preferably in the morning or late afternoon hours.

In the same way, another way to avoid the high presences of the insect on forage surfaces, is by using agroecological alternatives such as forage associations, either with herbaceous or shrubby species, since it contributes to the balance of the ecosystem, since the conventional management of the use of monocultures would be broken and a variety of organisms (predators, entomopathogenic organisms) that can contribute to the control of certain pests can be attracted.

Another way to keep the paddocks with low chances of being attacked by the insect, is by performing an appropriate zootechnical management by adjusting the animal load, that will avoid overgrazing and the pastures will be kept physiologically active with a rapid recovery after each cutting, which translates into an active competition for space, light and nutrients with the arvenses, decreasing the presence of these that can become hosts of the false meter worm.

In the previous section, the appropriate zootechnical management was mentioned to avoid the presence of high populations of the insect, but there is also a management that would be the opposite in case of high populations of the larva, which consists of increasing the animal load with the intention of causing an overgrazing creating an effect of competition for green biomass and in addition the animals destroy some larvae by the action of trampling, then fertilizers should be applied for the recovery of the pasture, it is necessary to emphasize that this strategy should not be carried out frequently because it could affect the availability of pasture in the paddock.

If the economic threshold is exceeded, observing a high insecticidal population in the paddocks, it is recommended to apply synthetic pesticides such as emulsifiable Malathion 1.0 kg i.a./ha when the larvae are small, you can also use pesticides whose active ingredient is carbaryl and carbofuran, but they become extremely toxic, which can lead to a decrease in beneficial biota. If this type of chemical products is used, it is recommended to remove the animals from the paddock for an approximate period of between 21-30 days, with the intention of preventing possible poisoning. Before this situation, the neem extract could be tested for its control, since good results have been observed in some experimental tests for the control of fall armyworm.

Dear agroecologists, as has been observed during the various publications related to insect pests, it has been possible to reflect that the biodiversity present in grasslands depends on many factors that intervene directly in the ecosystem, therefore the management to which the agroecosystem is subjected can bring both positive and negative consequences. Currently, the effects of climate change have generated an imbalance in agroecosystems, since the amount and distribution of rainfall during the year have varied a lot, which has affected the intermittent presence of pests, so we must know their biological cycles and follow up in our paddocks when we consider that there are the ideal conditions for the proliferation of any of them.

From agrotecnia we reiterate our gratitude to our followers and all the communities that value our agricultural content.

Aguilar, M. (2016). Diagnosis of the damage caused by the false meter (Mocis latipes) in the cultivation of sugar cane (Saccharum officinarumL.) at Finca San José Buena Vista. Unpublished degree work. University of San Carlos of Guatemala: Mazatenango Guatemala.

Alvarez, A. y Sanchez, G. (n.f.). Life cycle and description of the Mocis latipes worm. Rev. ICA, 16 (2), 57-63.