Pengendalian Hama Tikus dengan Burung Hantu

Burung hantu (Tyto alba) merupakan predator tikus yang sangat potensial pada perkebunan kelapa sawit. Predator ini mampu menurunkan serangan tikus pada tanaman muda hingga di bawah 5%. Sementara itu, ambang kritis serangan tikus di perkebunan kelapa sawit sebesar 10%.

Burung hantu mampu bertelur 2-3 kali dalam setahun, kemudian menjadi dewasa setelah berumur 8 bulan. Telur yang dihasilkan bervariasi antara 4–19 butir, bergantung pada ketersediaan makanan. Seekor burung hantu mampu memangsa tikus 2–5 ekor sehari.

Pada umumnya penanggulangan serangan tikus di perkebunan kelapa sawit dilakukan dengan menggunakan racun tikus (rodentisida). Namun cara ini dapat menyebabkan terjadinya pencemaran lingkungan dan dianggap tidak ekonomis.

Penggunaan burung hantu sebagai musuh alami merupakan satu alternatif penanggulangan hama tikus di perkebunan kelapa sawit yang sangat efektif dan efisien. Biaya pengendalian serangan tikus dengan burung hantu hanya berkisar 50% dibandingkan penanggulangan tikus secara kimiawi.

Tettigoniids are the most speciose of the ensiferan families. Ancestral Permian katydids (Sharov 1968) have diversified into almost 6000 living species in 1070 genera (Otte 1997). These large orthopterans (from 1 to 6 cm) are known as katydids in the New World and Australia-New Zealand (where one also hears “long-horned grasshopper”) whereas in Britain and Europe tettigoniids are “bushcrickets” (sauterelles in France, esperanás in Portugal, grillos in Spain, and Laubheuschrecken in Germany (Nickle and Naskrecki 1997)).

Katydids are found on all continents except Antarctica and in an assortment of habitats from tropical forests (Heller 1995) and peat bogs (Vickery and Kevan 1985) to montane alpine zones “far above the last outposts of trees”(Tinkham 1944). Within these habitats, virtually all tettigoniids are associated with vegetation, particularly during inactive periods when the insects retreat into (or onto) leaves. These habits are best known for cryptic species whose wings mimic leaves (Belwood 1990; Nickle and Castner 1995) or sticks (Rentz 1993: see title photographs) but even ground-dwelling, flightless katydids will use the cover of vegetation when inactive. In contrast, most other ensiferans use burrows in soil (Kevan 1989) and holes in wood (exceptions include vegetation-inhabiting grylloids such as Eneopterinae and Trigonidiinae).

Most katydids are omnivorous, feeding on vegetation, seeds, carrion and occasional prey. There are a few specialists such as the pollen-eating Zaprochilinae (Rentz 1993) and carnivorous Saginae (Kaltenbach 1990). Feeding by katydids can damage crops, but a significant economic impact is rare because population densities are usually low. Exceptions are tettigoniine and conocephaline pests (Jago 1997; Mbata 1992), especially species that aggregate in swarms or bands, e.g. the flightless Mormon crickets (Anabrus simplex) of western North America that migrate in large bands (MacVean 1987). Positive impacts on humans include the use of some katydids as food (MacVean 1987) and as “singing pets” in China where the market price for a “cultured” male songster can reach $US 16.00

Penyakit bulai disebabkan oleh jamur Sclerospora maydis. Bagian tanaman yang diserang adalah daun, terutama pada tanaman muda yang berumur di bawah 40 hari. Daun yang terserang berubah warna menjadi kuning keputih-putihan dan di bagian bawahnya muncul konidia berwarna putih, berbentuk seperti tepung. Serangan jamur ini akan meningkat pada suhu udara tinggi.