MANAJEMEN PENYAKIT TANAMAN Prinsip Utama Pengendalian

Penyakit Tanaman dalam Praktek Tujuan Pengetahuan/Konsep Diagnosis Pengenalan gejala, tanda Biologi Patogen Prognosis Siklus Penyakit Prinsip-prinsip Pengendalian Strategi dan taktik pengendalian Aplikasi Manajemen pertanaman

Prinsip Utama Pengendalian Sebelum patogen muncul Eksklusi = usaha mencegah introduksi atau menetapnya patogen Sesudah patogen muncul Terapi = prosedur – prosedur yang dilakukan setelah patogen muncul

Eksklusi Patogen 1. Karantina (Quarantine) = program atau kebijakan untuk mencegah introduksi patogen 2. Bahan tanam bebas patogen atau penyakit a. Certification of seed and other planting material b. Treatment of propagation material “Regulatory Plant Pathology” (Pengendalian dengan Peraturan / UU)

Penghidaran dari Patogen Menghidari penyakit tanaman dengan menanam: 1. Saat inokulum inaktif atau level inokulum rendah 2. Pada daerah atau area yang tidak endemis penyakit atau bebas inokulum atau yang lingkungannya mendukung. Memproduksi benih komersial di area yang jauh dari daerah endemis penyakit

Eradikasi Patogen Mengurangi, mengambil, membuang atau memusnahkan inokulum pada sumbernya baik pada area atau dari individu tanaman yang telah terserang Rotasi dengan tanaman yang dapat memutus perkembangan biakan patogen Perlakuan dengan bahan kimia, panas dll = soil sterilization for potting mix, fumigation Fungisida eradikan Pengendalian Hayati patogen tanaman

Melindungi Tanaman Mengurangi atau menghilangkan efektivitas inokulum pada daerah infeksi dengan memberi penghalang antara tanaman dan patogen Penyemprotan bahan kimian atau dusting daun Perlakuan benih Fungisida protektan

Ketahanan Tanaman terhadap Patogen Mengurangi efektivitas inokulum, dengan mengurangi keberadaan patogen Terapi/perlakuan pada tanaman sakit Mengobati atau meminimalisasi kehilangan oleh tanaman sakit dengan bahan kimia atau mengubah keparahan dengan memanipulasi lingkungan untuk mengurangi intensitas penyakit

Vanderplank’s Equivalence Theorem “Effects of host, pathogen and environment can be translated into terms of the rate parameter of an epidemic” Changes in any component has an equivalent effect on disease More-less susceptible host All affect More-less favorable environment amount of More-less aggressive pathogen disease

Therefore, disease management principles and practices are often centered around the concept of the Disease Triangle so that management tactics often seek to manipulate one or more of the components of the disease triangle.

Knowing how particular pathogens go through their disease cycle is important in developing management strategies.

Understanding how disease cycles relate to disease severity is assisted by the discipline of Epidemiology Epidemiology is “the study of factors affecting the outbreak and spread of infectious diseases” Or: the study of disease in populations, how diseases increase over space, in severity, or over time.

A central concept to epidemiology is that different pathogen populations have different disease cycles. I. Monocyclic = single cycle (simple interest) Pathogens that complete one or even part of one disease cycle/year are called monocyclic In monocyclic pathogens the primary inoculum is the only inoculum available for the entire season. There is no secondary inoculum and no secondary infection. The amount of inoculum produced at the end of the season, however, is greater than at the start of the season so the amount of inoculum may increase steadily from year to year.

This representation of plant disease over time is referred to as a “Disease Progress Curve” Graphically, disease caused by monocyclic pathogens looks like a saturation curve.

Examples of Monocyclic Diseases Blackleg of potato (Erwinia caratovora) Verticilliumwilt Cereal Cyst Nematode

II. Polycyclic = multiple cycles/year (compound interest) Most pathogens go through more than one (2-30) disease cycle in a growing season and are referred to as polycyclic. Only a small number of sexual spores or other hardy structures survive as primary inoculum that cause initial infections. Once infection takes place, large numbers of asexual spores are produced as secondary inoculum at each infection site. These spores can produce new (secondary) infections that produce more asexual spores and so on. With each cycle the amount of inoculum is multiplied many fold.

Many of these pathogens are disseminated primarily by air Or air-borne vectors and are responsible for most of the explosive epidemicsin most crops Examples of Polcyclic Diseases Downy mildews Powdery mildews Late blight of potato Leaf spots Blights Grain rusts Aphid borne viruses Root-knot nematodes

III. Polyetic (multi-year) cycles Some pathogens take several years before inoculum they produce can be disseminated and initiate new infections. May not cause many new infections over a given area in a year, amount of inoculum does not increase greatly within a year. However, because they survive in perennial hosts they have almost as much inoculum as they had at the end of the previous year. Inoculum may increase steadily(exponentially) from year to year and can cause severe outbreaks when considered over several years.

Examples of Polyetic Diseases: Some diseases of trees Dutch elm disease Pear decline Citrus tristeza Fungal vascular wilts Mycoplasmal yellows Viral infections

Implications for Disease Management Strategies Monocyclic Diseases Reduce the amount of primary inoculum, or affect the efficiency of invasion by the primary inoculum. Polycyclic Diseases Reducing the amount of primary inoculum has less impact. Reducing the rate of increase of the pathogen more beneficial

Principles of epidemiology indicates that control measures can do this in only two ways. 1. They may reduce (or delay) disease at the beginning of the season (Xo) or 2. They may decrease the rateof disease development (r) during the growing period.