Preliminary study on the biology, natural enemies and chemical control of the invasive Macrohomotoma gladiata (Kuwayama) on urban Ficus microcarpa L. trees in Valencia (SE Spain)

Autores UPV
Año
Revista URBAN FORESTRY & URBAN GREENING

Abstract

The phenology and natural enemies of Macrohomotoma gladiata (Kuwayama) (Hemiptera, Homotomidae) on Ficus microcarpa L. in Valencia (Spain) were studied in 2013. During the study, all immature instars of the pest were found on infested shoots indicating overlapping generations. However, two consistent increases in the proportion of the first two nymphal instars were detected in early March and June, possibly suggesting the beginning of spring and summer generations. Eggs of M. gladiata were usually found below the stipules of new healthy shoots, arranged in groups of 15¿30 units. First two nymphal instars usually preferred the innermost part of the shoot, whereas the older developmental stages were localised more externally. The abundance of pest population increased in February¿April and lowered from May onward. A number of other pest species were collected on the sampled trees. These included: Gynaikothrips ficorum (Marchal) (Thysanoptera, Phlaeothripidae), Pseudococcus longispinus (TargioniTozzetti) (Hemiptera, Pseudococcidae) and Greenidea ficicola Takahashi (Hemiptera: Aphididae). Unlike M. gladiata, the populations of these insects on shoots remained high from May onward. Among natural enemies of the invasive pest, Prionomitus mitratus (Dalman) (Hymenoptera, Encyrtidae) and Anthocoris nemoralis (Fabricius) (Hemiptera, Anthocoridae) were the most abundant. The encyrtid is here reported for the first time as a parasitoid of M. gladiata. Its presence was constant all along the study period, with a peak in May and June and an apparent preference for the older instars (third to fifth nymph stages) was recorded. In an attempt to indicate a possible remedy to the heavy infestations of M. gladiata, and considering the urban location of the sampled trees, two pesticides, a paraffin and a botanical oil, were tested. Treatments significantly reduced the population of the psyllid. The botanical oil resulted more effective than paraffin oil in reducing the number of the first two nymphal instars, regardless their innermost position on infested shoots.