Mocis latipes/ pasture pest

Dear readers, in livestock production systems forage areas are mostly established by species belonging to the family of grasses known as poaceae, generally in these areas there are outbreaks of chewing arthropods, whose habit of consumption generates heavy damage to the pastures that result in significant economic losses, This often occurs due to the lack of knowledge about the agronomic management of pasture because it is not considered as a crop in certain production units.

For all of the above, in this opportunity we will address some aspects of agro-productive interest for the efficient management of Mocis latipes, considered a pest that causes serious damage to pasture crops.

The Mocis latipeses, commonly known as false grass cutworm or grass peeler worm, the first name is associated with the way the larva moves, as it stretches and shrinks the ends and arches the middle part of the back as if it were measuring, On the other hand, the second name is associated with the damage it causes to plants, because it defoliates the leaves leaving only the midrib if there is no timely control, this habit is very similar to that exercised by Spodoptera frugiperda.

The appearances of this insect are generally seen in tropical conditions and according to Espinoza (2016), it belongs to the genus Mocis spp, order Lepidoptera, family Noctuidae and can also be located through different synonymies such as Remigia latipes, Ophuisa delinquens, Remigia exscindens, Remigia subtilis, Remigia collata, Remigia indentata, the arthropod has a chewing mouthparts with which it causes a chopping of the leaf blades; Like Spodoptera, it is polyphagous, since it has a preference for different crops such as sorghum, rice, wheat, sugar cane and pastures, all of which, as can be seen, are part of the Poaceae family.

Similarly, among the species of grasses susceptible to attack by Mocis l. reported by different researchers and producers in tropical areas are the following: Cynodon nlemfuensis (star grass), Melinis minutiflora (gordura grass), Urochloa arrecta (tanner grass) and another less susceptible but which has been affected by the meter is Megathyrsus maximus (guinea grass).

The meter worm, to reach its adult stage, goes through a metamorphosis or shape changes that will be described as follows:

*Egg stage: the adult insect generally lays its eggs near the midrib of the leaves, some authors point out that specifically on the underside of the leaves, but in some field reviews ovipositions have been observed on both sides of the leaf, on the other hand according to Aguilar (2016), the eggs hatch after 4 to 6 days approximately, similarly another data of interest reported by Alvarez and Sanchez (n. d.), is concerning the start of the oviposition process, noting that females begin this process on the third day after emerging from the pupa, important information since it can be observed how quickly the females begin the process of oviposition. f.), is concerning the beginning of oviposition, pointing out that females begin this process on the third day after emerging from the pupa, important information since it is possible to observe the speed with which the insect population spreads at the time of reaching its highest stage of maturity.

*Larval stage: In this stage, because it is detrimental to the foliage of pasture crops, we consider important to refer to an experiment conducted by Alvarez and Sanchez (n.d.), where they observed in detail the changes that occur in the life cycle of this species and specifically in the larval stage, since they were able to provide interesting information that allows establishing management strategies in the crop. The aforementioned authors determined that the larval period has a duration range between 14 and 22 days approximately, obtaining an average of 18 days, during the mentioned period they go through six instars until they reach their adult stage.

During the different instars the researchers were able to determine some damage caused by the larvae as they increase their maturity and at temperatures of 32 °C which are the temperatures between which oscillate some tropical areas such as certain areas of southern Lake Maracaibo, such damage has been corroborated in the forage surfaces of the southern area of the lake to perform some inspections especially in pastures of Melinis minutiflora (fat grass). Next, in image 3 will be detailed the days that remain the larvae in each instar.

*Pupal stage: as mentioned in the Spodoptera frugiperda article, the pupal stage is a transition stage where the insect stops being a larva and prepares to become an adult, the insect forms a kind of hard shell where it will remain for a certain time without eating and moving until it leaves the pupa and becomes an adult. In the case of Mocis latipes they pupate in the leaves of weeds or in pasture crops, they generally tend to fold the leaf and roll up in it with a kind of soft thread that they secrete, the pupae as the days progress change color starting with a color to green until culminating with a dark brown color, in this way is that they form their compartments where they will remain approximately 5 to 11 days depending on the temperatures as reported by the foundation service for the farmer FUSAGRI.

According to the above mentioned regarding temperatures, it is necessary to mention that according to the National Institute of Agricultural Technology INTA, the pupal stage is the form of resistance for the winter period, a situation that does not interfere in our areas, since they do not register very low temperatures that can raise their mortality levels, for such reason the pupal period mentioned above will be fulfilled until reaching its adult stage without significantly interfering with low temperatures.

*Adult stage: the adult can be considered a moth or nocturnal butterfly brown color, with an approximate size of 2 to 4 cm approximately, has nocturnal habits being placed on the foliage of grasslands or weeds, the butterfly remains in this stage about 17 days and as mentioned above can get to place their eggs on the third day of emerged approximately by any of the two sides of the leaf (beam and underside), near the midrib, thus starting the cycle again.

Dear readers, the biological cycle of the insect has an average duration of 35 days, in image 5 it can be observed that according to the approximate ranges in days it can reach a maximum of 66 days, this can occur according to Espinoza (2016), in regions with temperate climates where the cycle could be extended between 60 and 80 days approximately, possibly because temperatures decrease considerably and the insect would remain more days in its pupal stage.

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

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