Important diseases of the olive and their management through fungicides and Biocontrol.
Ghulam Muhae ud Din1, Muhammad Amjad Ali1, Muhammad Usman1, Hafiz Muhammad Uzair Saqib2
1Department of Plant Pathology, University of Agriculture, Faisalabad.
2Department of Forestry and Range Management, University of Agriculture, Faisalabad.
History of the olive in the Pakistan
Olive is the tree like plant which bear fruits are small oval like with the hard pit, they are green in colour during the unripe stage, but change into brownish black at the ripening stage. Olive was first introduced in the Pakistan through the help of Punjab Agriculture Research Council (PARC) under a project of “Fruit, vegetable and olive” which was funded by Government of the Italian. At the end of this project, a general survey was conducted to estimates the Olive species in different district of the Punjab, and founded more than 80 million wild olive plants.
Importance of the Olive
Olive is the good source of the edible oil and used as a table purpose particularly as the pickles. Olive fats are free from the cholesterol, and used as the medicinal plants for different purpose. Olive oil is used to prevent colorectal cancer, heart attack, breast cancer, stroke (cardiovascular disease), migraine headache and rheumatoid arthritis. Some people use olive oil to treat constipation, high blood pressure, high cholesterol, constipation, blood vessel problems associated with diabetes and arthritis, pain associated with ear infections and gallbladder diseases, while oil have potential to treat intestinal gas, jaundice and meteorism (swelling of abdomen due to gas). It also used to activate the gut bacteria as a “cleaner” and “purifier”. Oil is applied for the skin treatment for ringing ears (tinnitus), earwax, lice, pain in the ears, psoriasis, wounds, stretch marks due to pregnancy, minor burns and protect the skin from the ultraviolet. It may be used in textile industry, food and cosmetic preparation along with the variety of the other beneficial purpose. Olive oil is one of the widely used culinary oil and their fats are present in the form of oleic acid (a monounsaturated, omega-9 fatty acid). In respect to the nutritional and medicinal purpose olive fruits is the blessing of Allah Almighty. Olive has been referred in the noble way by the Holy Quran and its importance is clarified by many saying of the Holy prophet Hazrat Muhammad (S.A.O.W). In foods, oil is used as a cooking and salad oil. In manufacturing, oil used in the soap, liniments and commercial plasters.
Pathogens attack on the olive plants
Most important diseases of the olive plants are caused by the pathogenic fungi, bacteria, viruses and nematodes. Fungi are unable to produce their own sugar molecules, due to the absence of chlorophyll which is the important element of photosynthesis. Bacteria mostly attack on the human and animals instead of the plants, while in some conditions they pursue the highly losses in the agriculture by causing the epidemic disease of the cash crops. In agriculture it is very difficult to prevent the bacteria through cultural practices, they can be controlled by the bactericide and antibiotics which are very expensive and not easily affordable by the farmers at commercial level, so the best way to eradicate the pathogenic bacteria by “cutting of branches or covering up the plants by different methods”. Most popular and important disease of the olive plants which are caused by the fungi are given below.
Peacock spot
Its technical name is Cycloconium oleaginym Cas, which is caused by the fungus Cycloconium oleaginum. the most obvious symptoms of the peacock spots is the appearance of the grey, black, or dark circular spots on the upper and lower surface of the infected leaves under favorable conditions. Later on these infected leaves are turn into yellowish color and at the end of the spring leaves will detached from the main branches of the plants. Due to the defoliation, the yield production of the olive tree becomes near to diminish.
Figure 1. Peacock spot of olive
Verticillium Wilt
This type of fungus was present in the soil and under favorable conditions this fungus penetrates in the root zone of the olive plants and start to infect the host. Verticllium wilt is rare in the traditional olive cultivars, while this disease is favored in the overcrowded plantation of the olive. With the infection of the verticillium fungus vascular system of the olive plants become clogged and as a result water and nutrients become unable to move freely in the plants, so secondary buds and infected branches become wither and in severe cases primary buds will be die. The infected leaves of the olive plants fold inward and at the end branches of the tree die. Vessels of the olive become clogged, water and nutrients cannot move properly so secondary buds and branches become wither and sometime in worse case primary ones will be died. The infected leaves fold inward and at the end branches die.
Figure 2. Verticillium wilt of olive
Fruit rot or Olive Anthracnose
The fungus responsible for the fruit rot or olive anthracnose, belong to the phylum (Deuteromycetes). This type of fungus have great potential to attack on the leaves , buds and wood of the olive plants It is most deleterious disease of the olive and more than 40% losses were recorded due to the fruit rot under favorable condition in the humid region. Rotting and mummified are the foremost symptoms of the olive anthracnose. Although defoliation and drying out of the branches appeared in the highly affected olive plants.
Figure 3. Fruit rot or olive anthracnose
Olive Shield
Although this disease have minute effect on the physiology and morphology of the olive plants but it change the quality of the oil by increasing the acidity, and sometime it has potential to change the flavor of the oil under adverse condition. Dark circular spots are the prominent symptoms of the disease, which look like the shield.
Figure 4. Olive shield disease
Management
- Cultural practices
Olive plants are good ventilated, there must be pruning to remove the condensation condition in the area of the olive plantation.
- Chemical control
Topsin M, Captan, Copper oxychloride, Zinab, Native, Bordeaux mixture, Cuprous oxide, Captafol, Benomyl are mostly used to manage the fungal diseases.
- Biocontrol
Trichodema spp, Bacillus spp and Pseudomonas spp used as the Biocontrol to control the diseases of the olive.
