Bożena Łagowska

The effect of a mealybug infestation on the activity of amino acid decarboxylases in orchid leaves

Changes in the activity of lysine decarboxylase (LDC), tyrosine decarboxylase (TyDC), and ornithine decarboxylase (ODC) within orchid (Phalaenopsis × hybridum ‘Innocence’) leaves, infested by two mealybug species: Pseudococcus longispinus (Targ. Tozz.) and Pseudococcus maritimus (Ehrh.) were quantified. The pattern of changes was dependent on the insect species and duration of infestation. P. longispinus feeding increased LDC and TyDC activity after one week during the total period of observations. This species inhibited ODC activity after one week but increased later. P. maritimus decreased LDC activity in orchid leaves at all studied terms. TyDC action also went up during the first week of the infestation and was reduced after two weeks, while ODC was decreased after one day and induced later. The mechanism for the participation of analysed amino acid decarboxylases in local and/or systemic steps of orchid responses to mealybug infestation is discussed.

Physiological Response of Orchids to Mealybugs (Hemiptera: Pseudococcidae) Infestation

Abstract The harmfulness of mealybugs resulting from sucking plant sap, secreting honeydew, and transmitting plant viruses can give them the status of serious pests. This study documents the influence of Pseudococcus maritimus (Ehrhorn) and Pseudococcus longispinus (Targioni Tozzetti) infestation on alterations in selected physiological parameters of Phalaenopsis x hybridum ‘Innocence’. The condition of the cytoplasmic membranes was expressed as the value of thiobarbituric acid reactive substances. We have determined changes in the activities of catalase and guaiacol peroxidase and measured the following chlorophyll fluorescence parameters: maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield (Y), photochemical quenching (qP), and nonphotochemical quenching (qN). The strongest physiological response of orchids was recorded in the initial period of mealybugs infestation. Prolonged insect feeding suppressed lipid peroxidation, peroxidase and catalase activity, as well as photosynthesis photochemistry. The pattern of changes was dependent on mealybug species. This indicated the complexity of the processes responsible for plant tolerance. Data generated in this study have provided a better understanding of the impact of two mealybug species infestation on Phalaenopsis and should be useful in developing pest management strategies.

A new species of Marsipococcus Cockerell & Bueker (Hemiptera: Coccomorpha: Coccidae) from Malaysia

The adult female, first-instar nymph, second-instar male, third-instar female, pupa and adult male of a new species of Marsipococcus Cockerell & Bueker (Hemiptera: Coccomorpha: Coccidae) from Malaysia, M. ulubendulensis Łagowska & Martin sp. n., are described and illustrated, while the second-instar female is only described. Marsipococcus is rediagnosed and a key to the adult females of the four species now placed in this genus is included.

A new species of Bambusaspis Cockerell (Hemiptera: Sternorrhyncha: Coccomorpha) colonising bamboo in Malaysia.

All life stages (adult female and male, first-instar nymph, second-instar male and female nymphs, and prepupa and pupa) of a new species of Asterolecaniidae, Bambusaspis transversa Lagowska & Martin sp. n., from bamboo in Malaysia, are described and illustrated. The adult female and first-instar nymphs are compared with those Bambusaspis species considered to be closest to the new species.