Quantitative analysis of potency of acerophagus papayae noyes & schauff (Hymenoptera: Encyrtidae), parasitoid of the papaya mealybug

Abstract

The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), was an invasive pest that invaded Indonesia in early 2008 and caused heavy damage on papaya. One of the natural enemies found in Bogor was parasitoid Acerophagus papayae Noyes and Schauff (Hymenoptera:Encyrtidae). The parasitoid was believed to have been fortuitously introduced into Indonesia. Research was conducted to evaluate the potency of A. papayae as biological control agent for the papaya mealybug. Studies included determining various biological parameters such as development time, host preference, functional response, and simulation model of host-parasitoid population dynamics. Parasitoids were obtained from the papaya fields by collecting the mummy of papaya mealybugs and enclosed individually in gelatin capsules. Adult parasitoids emerged were reared on the papaya mealybugs with Jatropha curcas as a host plant. Fitness and preference of the parasitoids were studied using papaya mealybug instar II dan III with a piece of papaya leaf in a test tube (d = 3 cm, h = 15 cm). Functional response of the parasitoids were studied at the host density of 2, 5, 10, 20, 30, 40, and 50 nymphs. Mummies were also collected from the fields, and the data were used to test the sensitivity and validate the model using Stella version 9.02 software. Our study revealed that the parasitoid preferred second-instar over the third-instar nymphs of P. marginatus. Immature developmental time was shorter and survival rate was higher of parasitoids developed on the second-instar nymps. Female parasitoid showed type II functional response with the increasing host density. Our simulation model indicated that the parasitoid had a good searching capacity and was able to regulate papaya mealybug population.

Kutu putih papaya (KPP), Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae), merupakan hama asing invasif yang masuk ke Indonesia pada tahun 2008 dan banyak menimbulkan kerusakan berat pada pertanaman pepaya. Salah satu musuh alami yang ditemukan di Bogor adalah parasitoid Acerophagus papayae Noyes & Schauff (Hymenoptera: Encyrtidae). Parasitoid ini diduga masuk ke Indonesia secara tidak sengaja bersama inangnya. Penelitian bertujuan untuk mengevaluasi potensi parasitoid sebagai agens pengendalian hayati KPP, melalui kajian terhadap aspek kebugaran parasitoid, tingkat parasitisasi, kapasitas reproduksi, nisbah kelamin dan tanggap fungsional serta pemodelan sederhana interaksi KPP dan parasitoid A. papayae. Penelitian dilaksanakan di Laboratoriun Ekologi Serangga, Departemen Proteksi Tanaman, Fakultas Pertanian, Institut Pertanian Bogor. Penelitian berlangsung sejak Juli sampai Desember 2010. Imago parasitoid A. papayae didapatkan dari lapangan dengan mengumpulkan mumi kutu putih pepaya terparasit yang kemudian dimasukkan ke dalam kapsul gelatin. Imago parasitoid yang muncul dipelihara pada KPP dengan menggunakan tanaman inang jarak pagar kurkas. Penelitian kebugaran dan preferensi menggunakan KPP instar II dan III yang dipaparkan pada helai daun pepaya yang diletakkan dalam tabung reaksi (d = 3 cm, t = 15 cm), dan berlangsung selama hidup imago betina A. papayae. Percobaan tanggap fungsional dilakukan pada cawan petri, dengan kerapatan inang 2, 5, 10, 20, 30, 40, dan 50 ekor nimfa. Untuk mengetahui kinerja parasitoid selama penelitian berlangsung dilakukan pengumpulan mumi dari lokasi perkebunan buah pepaya di Fakultas Perikanan, IPB. Hasil pengumpulan mumi dari lapangan digunakan untuk menguji sensitivitas dan validasi model secara kualitatif. Pemodelan menggunakan piranti lunak Stella versi 9.02.