Knowing the difference between the effects of pests and diseases in plants can help you to better understand what the plants need to get better. Let’s find out a little more about pests and diseases in plants.
Pests in plants and what they attack
As stated in the Ministry of Agriculture Cyber Extension websites, the definition of pest in a sense that is related to plant cultivation activities are all animals that damage plants or their products, which can cause economic losses. Animals can exist in one crop without causing economic losses, this does not constitute the animal as a pest. However, their potential as pests will need to be monitored.
Pests that are generally a threat to agricultural activities can be classified into Nematodes (worms), Mollusks (snails), Arthropods (insects and mites), and rodents (rats). Other animals that could pose a threat to plants depending on where it is grown are birds and wild boar. These pests attack the plant in the roots, stems, leaves, and other parts that could generally disrupt the growth of the plants. The pests typically feed on the plants and the growth disruption can cause the plant to be stunted and die.
Most pests are organisms that can be seen with the naked eye therefore they are easy to identify and treat. As mentioned, they feed on the plants and cause physical harm because of the way they take water and food from plants. Here are a few damages that pests can cause in plants to look out for:
- Withered plant
- Stains on leaves (yellow, brown, or black)
- Bites on leaves and stems
- Falling leaves
- Dried leaves
Disease in plants and its symptoms
Disease in plants is anything that causes disturbance to the plant so that the plant cannot reproduce properly and causes the plant to die slowly. It is usually the result of the action of biotic or abiotic agents.
Abiotic or non-parasitic are changes caused by non-living things such as climatic conditions, lack of supply of nutrients, presence of pathogenic molecules, chemical toxicity as a result of insecticides, etc. While Biotic agents are from the group of fungi, bacteria, and viruses. The biotic agents are pathogenic organism that causes disease in plants in the following ways:
- Continuously absorbing nutrients or cell contents that weaken the host plant. Examples are bacteria, parasites, and viruses.
- Killing cells or destroys the metabolic activities of the host cells by releasing substances, such as enzymes or toxins into the host cells. One example is the mold that causes leaf wilting in potatoes (Phytophthora infestans)
- Interfere with the transport of nutrients, minerals, and water in the host’s transport vessels. One example is the fungus that causes leaf wilting in tomatoes (Fusarium oxysporum)
- Obstruct the process of photosynthesis.
The disruption that is caused by plant disease can be harder to see and treat. The disease can slowly develop and if left untreated it can cause the plant to slowly weaken and die. That is why it is important to always watch for signs to diagnose disease problems in time to control them. A few symptoms to look out for are:
- Abnormal local swelling
- Loss of stiffness and drop of the plant
- Inability to develop or abnormal development
- Stains on leaves or fruits
- Plant tissue death.
How to control Pests and Diseases?
Pest and diseases are biotic stresses that can reduce yields and even cause crop failure. Therefore, to obtain optimum yields, it is necessary to control the threat of pests and diseases. An Integrated Pest Management or Pengendalian Hama Terpadu (PHT) is a control approach recommended by the Ministry of Agriculture that takes into account ecological control factors. The ecological control factors are taken into account so as not to disturb the natural balance and cause further losses. PHT can be used with a big farm or a small garden to ensure the continuation and health of the soil and plants.
The PHT approach takes into consideration the ecological effects and economical efficiency to control plant pest organisms (OPT). While it may be easy and have an instant result to use insecticide or fungicide when a symptom arises, continuous use of it can cause immunity and new strain to arise, even an explosion of pest population in the long run. PHT can maintain the diversity of plant disturbing organisms without eradicating them. The approach controls the pest populations so that it remains below a level that does not result in losses.
There are many methods in controlling pests and diseases in plants. Each method can be combined depending on the size of the threat. The methods are:
- Mechanical methods for pest by handpicking the pest and killing them, setting up traps, and putting up nets
- Cultural methods by choosing plant varieties that are adapted to the site conditions, and are tolerant of insects and diseases, rotating crops, interplanting, timing planting dates to avoid pests, and environmental sanitation.
- Biological methods by using natural enemies of the pest and pathogens. Examples of the natural enemies of pests and pathogens can be predators, larval parasites, and egg parasites.
- Chemical methods by using chemicals, both organic and inorganic.
The threat of pests and disease are constant and can cause the death of the plants. It is important to gradually control your plants to make sure that the effects of the pest and disease are not significant and kill your plant. Other than methods of controlling pests and diseases threats, making sure that your plants are healthy, as well as providing them with environmental conditions they need for healthy growth, are the keys to keeping your plants free of pests and diseases.