**Abstract**

Areca nut has source of complex carbohydrates and natural fiber for humans. Almost all parts of this plant can be utilized. This plant is a commodity with high economic value in Indonesia. Moreover, the daily consumption of areca nut is passed down from generation to generation, a tradition is known as 'chew *Pinang*'. The seeds of this plant are always present in the completeness of several traditional events in Indonesia. The development of this plant encountered challenges such as decreased productivity levels due to infection with pathogenic microorganisms. Pathogens that attack areca nut commodities can be in the form of bacteria and fungi. Leaf midrib rot is caused by the mycelia of the pathogenic fungus *Athelia rolfsii*, in addition to infection with *Penicillium* sp. during plant growth also results in losses. *Phytophthora arecae*, Micoplasm-like Organism (MLO), *Ganoderma lucidu*, *Colletotrichum gloeosporioides*, *Curvularia* sp., *Pestalotia palmarum* Cooke., *Cephaleuros* sp., *Ganoderma lucidum*, *Fusarium* sp., *Rhizoctonia* sp., *Xanthomonas campestris*, *Ceralostomelia paradox.*

**Keywords:** areca nut, Indonesia, microorganism, pathogen, plant diseases

#### **1. Introduction**

Areca nut belongs to the category of straight trunked trees with a height of up to 30 meters and a diameter ranging from 25 to 40 meters. The average life span is up to 60 years and some species can reach 100 years. This plant is estimated to be native to Sulawesi (Celebes) Indonesia, Malaysia, and New Guinea [1]. It's distribution covers the tropics in Asia, the Pacific, and parts of East Africa. Areca nut is known by the names beter palm nut, catechu, areca nut, and many other names. This plant can adapt to disturbed land, swamp forest edges, and creeks.

Almost all parts of this plant are economically viable for humans. Plant morphology Areca nut has pinnate leaves with a length of 1-1.5 meters. The base of the midrib leaf is gray and has a crown shape. Branched flower stalks reach a length of 1 meter and grow from under the crown stalk. The fruit has red or orange seeds with a length of 5-6 cm and a width of 4-5 cm. The shape of the fruit varies from round to slightly flat. Taxonomically, Pinang is included in the Spermatophyta division, Monocotyledone class, Order Arecales, Family Arecaceae, and Genus Areca [2].

Areca nut is known as a plant with benefits in every organ it has. These benefits include areas in human life and their role in the ecosystem. The presence of several bacterial phyla (*Proteobacteria* and *Actinobacteria*) in this plant's rhizosphere is known to synergize to help maintain the balance of nutrient cycles in the soil

around the roots, thereby maintaining overall betel nut health and increasing plant productivity. This is related to the production of growth hormone, the enzyme 1-Aminocyclopropane-1-Carboxylate (ACC) deaminase which triggers growth and activity against plant pathogens. On the other hand, the use of this plant tree as a yard and garden plant [3]. The stems of this traditional community in Indonesia are used as an important ingredient in the areca climbing competition on Indonesia's independence day by every region in this country. The tradition of the fishing community throws betel leaves into the sea to invite fish to come. In the field of textile dye development, areca nut contributes as a natural dye for Sasirangan batik in South Kalimantan, Indonesia [4]. Areca nut is also reused as ornamental lighting commodities which have a selling value [5]. Young betel nut juice is commonly consumed by the public. Processed smoked betel nut becomes a light snack and is usually used as souvenirs typical of districts in Aceh, Indonesia. In addition, the cosmetic industry has also used betel nut powder as an additional ingredient in the production of transparent soap [6]. Its role in the ecosystem includes a part of agroforestry as an improvement in economic, ecological, and social systems [7]. This cultivation system makes it possible to grow seasonal crops together with crops that can be used in the livestock sector [8]. In addition, areca nut is used for erosion control (dune stabilization) and soil improvement [9].

Based on the description above, the productivity of this plant is very important to be maintained. Disease disturbance in plants is a problem that should be found a solution. Some of the symptoms of areca nut disease and matters that are closely related to the factors that cause the severity of the disease are discussed in this chapter.

## **2. Factor causing plant disease**

Plant health can be a factor that supports plant productivity. A simple definition of a plant health disorder can mean an imbalance in the proportion of normal growth and development caused by biotic and abiotic agents. Abiotic factors such as temperature, humidity, gas atmosphere, and light intensity that provide access to the presence of plant pathogens, decrease productivity or cause plant death directly. Several factors above interact with each other in achieving a state of balance in achieving plant health. Abiotic agents that cause disease in this case are environmental stress conditions and their handling and cultivation. While the biotic agents in question are plant pathogenic infections, including bacteria, fungi, and viruses.

#### **2.1 Abiotic factors**

Season (rainy and hot in Indonesia), summer lasts a chance to make the roots dry out, morphologically the roots will shrivel and die. This condition is caused by not allowing the roots to function in absorbing water from the soil.

Low humidity increases evaporation in plants so that moisture stress can occur. When the water supply to the leaves is inadequate, the concentration of the hormone abscisic acid increases rapidly, causing the leaf stomata to close. This process is known to protect plants from excessive water loss. Low humidity in outdoor situations is not usually a problem. This condition is often temporary and rarely results in reports of serious damage. However, if this condition is combined with other factors and occurs at the same time then symptoms of plant disease can appear. These symptoms are temporary to permanent wilting of plants, burnt leaves, and shriveled/wrinkled fruit

#### *Plant Diseases of Areca Nut DOI: http://dx.doi.org/10.5772/intechopen.107504*

due to excessive loss of water content. High humidity allows evaporation to occur in plants, inhibiting nutrients from being absorbed by plants. Impaired absorption of nutrients can have an impact on cell formation disorders. For example, plants with young fruit skins are prone to cracking during periods of prolonged high humidity. This provides an opportunity for further pathogens to infect exposed fruit parts without skin dressing.

The temperature fluctuates, while plant physiological activities such as photosynthesis, respiration, membrane permeability, absorption of water and nutrients, transpiration, enzyme activity, and protein denaturation can be directly affected by temperature. The response of plants to the minimum, optimum and maximum temperatures can be different for each plant. Likewise in plants in different places in the same physiological process. In general, plants that grow at the upper and lower limits of the optimum range tend not to grow as well as plants that grow at the optimum temperature range. Sexual organs such as fruit and flowers will grow smaller than plants that grow at optimum temperatures.

The lowest temperatures can cause damage to plant tissue, the level of damage will be exacerbated by stable low temperatures for a long time. Low temperatures can damage the young meristem webs, damaging the tips of young roots. The leaves of the plant will appear yellow and fall. Plant cells can be damaged because low temperatures disrupt the stability of the cell membrane to damage the entire contents of the cell. From low temperatures to freezing points, ice can also damage cell membranes and other vital materials in plant cells. High temperatures can cause damage in the form of coagulation and denaturation of plant proteins, disruption of cell membranes, and secretion of toxins into cells, resulting in cell death. This is through a slowed-down protein synthesis process, the production of 'heat shock proteins to defend the plant from damage. The severity depends on how high the temperature is and the length of exposure.

Wind speed factors affect the spread of plant diseases caused by fungi. This is related to the carrier and spread of conidium and the ability to stick to the plant surface. Light intensity affects several things such as exudation, sporulation, and the dispersion and growth of fungal conidium in the soil. Basically, with adequate light intensity, plant diseases can spread quickly, especially plant diseases caused by fungi. This is supported by related research explaining that conidium *Cercospora* in tobacco can spread and cause picking disease [10]. It also includes environmental imbalances such as air pollution (ozone, hydrogen fluoride, sulfur dioxide, ethylene, and peroxyacetyl nitrate).

#### **2.2 Biotic factors**

Pathogenic infections such as bacteria, fungi, and viral pathogens can cause the severity of symptoms that appear and play an important role in the spread of areca nut disease. An explanation of these biotic factors will be discussed in the next section.

#### *2.2.1 Plant disease symptoms*

We often observe sick plants in the field. To facilitate sample collection activities, field observation methods are needed. The methods used in field observations on symptoms of plant disease include:

a.Absolute method, observation of plant disease symptoms was carried out thoroughly by the population in the field. The resulting data will represent population estimates in numbers and individuals per unit of the land surface.


If in the field they have found a method to observe plant disease symptoms, of course, the next step is researchers must be skilled in determining plant disease assessment techniques, here are some things that need to be considered:

i. severity,

ii.describe and compare the symptoms and severity of the disease,

iii. scoring of symptoms,

iv. calculate the attack rate or disease index.

The description below will describe some of the diseases in Pinang caused by. microorganisms in the tropics and subtropics:
