First record of the cacao plume moth Michaelophorus nubilus (Felder & Rogenhofer) (Lepidoptera: Pterophoridae) in Mexico

T R A C T We report field infestation under natural conditions by the cacao plum moth, Michaelophorus nubilus (Felder & Rogenhofer) on leaves of cacao (Theobroma cacao L.; Malvaceae) for the first time in Southern Chiapas, Mexico. The larvae of M. nubilus damages new “flushing” or light green leaves from buds, from either the main or

In the Soconusco region of Chiapas, Mexico, records of insect pests and their damage to cocoa crops are practically nil. Therefore, it is essential to identify and determine the damages caused in cocoa plantations, as well as the different life stages of any insect pest that will facilitate the development of integrated management strategies to reduce such pest populations. We are thus reporting for the first time the cocoa plume moth M. nubilus damaging new leaves of T. cacao in Mexico.
Several plantations of T. cacao were surveyed in the Soconusco region, Chiapas, Mexico, during May 2018. After a careful visual inspection of new leaves and branches samples of leaves infested with larvae or pupae M. nubilus were manually collected. The visited and surveyed places are listed in Table 1.
Some larvae of Lepidoptera feeding on buds of cocoa plants were collected from all the previously mentioned plantations and sites. Ninety-five larvae were collected and brought to our lab at INIFAP where they were placed in groups of 10 larvae into 1-liter plastic containers covered with organdy fabric and fed daily with fresh new leaves of T. cacao until pupation. After five days, 77 adults emerged and were mounted to be later identified using the keys and descriptions provided by Gielis (2006) and Meyrick (1916). All identified specimens were collected under the scientific collector license FAUT-0194 SEMARNAT-CITES and have been placed in the Lepidoptera Collection of the Faculty of Biology at Universidad Veracruzana, Xalapa, Veracruz, Mexico (Key SEMARNAT-CITES: DF-CC-276-13).
All emerged adults were identified as M. nubilus. This species is characterized by having a dark brown forewing, with a faint subterminal line on both lobes, a discal spot surrounded by pale scales and its  abdomen is white (Gielis, 2006). The last instar larvae have a translucent cuticle and are mainly whitish or yellowish-green. The most relevant feature of the larvae is the length of their D2 setae on their abdominal segments. However, all D2 are long but notably shorter in A2, A4, A6, and A8 than in the adjacent segments. The pupae are anchored to leaves or branches (Fig. 1) and have a lime-green body, but their head, thorax, and appendages become dark brown before emergence (Matthews and Miller, 2010).
Damage and presence of larvae were observed throughout every month of the year in most locations with cocoa plantations that were monitored in southeast Chiapas, Mexico, regardless of the genetic group to which the plant belongs to (criollo, trinitario or forastero). The larvae of M. nubilus specifically feeds on new "flushing" or light green leaves from buds, from either the main or lateral branches (Fig. 1A). Some of the new leaves were found with up to 15 larvae feeding on them. Even though we were unable to measure foliar consumption, we noticed that in several shoots, over 50% of the leaf blade was consumed. Larvae close to pupation, were not very active when disturbed and they rested on the pedicel or the shoots' stem (Fig. 1B).
The pupae can be dark green or brown and are located mainly on mature leaves and branches, rarely on the main vein of young leaves (Fig. 1C). Some adults (Fig. 1D) were observed in orchards with a lot of shade and little agronomic management. The cacao plume moth has been previously reported in cocoa from Honduras, Costa Rica, Trinidad, Colombia, Venezuela, Ecuador, Peru, and Brazil (Lamont and Callan, 1950;Brito Silva, 1980;Gielis, 1999;Matthews and Miller, 2010). However, this is the first report of M. nubilus from Mexico attacking plants of T. cacao, its only known host so far (Gielis, 2006;Matthews and Miller, 2010).
In conclusion, M. nubilus deserves more studies in the cocoa plantations of Chiapas, Mexico, to learn more about its bioecology to propose management measures.