Budidaya Kelapa Sawit Berkelanjutan / Ganoderma

Download: Module 5: Pests and Diseases

Background

Figure 11: Ganoderma infection

Ganoderma, also known as basal or upper stem rot, is a fungal infection of the oil palm. In severe cases of a Ganoderma infection, the oil palm dies. Older plantations may have over 50 percent death rates in the event of a severe infestation. While there is no cure for a Ganoderma infection, the spreading of the infection can sometimes be limited through good management.

Ganoderma is spread in two ways:

1. Through soil by threads of fungus;
2. Through air by spores which come from a mushroom (bracket) that grows on the trunk of infected palms .

Not all infected palms have brackets on their trunk. When a palm is infected with Ganoderma, different symptoms may be seen, such as a yellowing of the young leaves, an accumulation of several young unopened leaves (spear leaves) in the middle of the canopy, or a ring of dead fronds hanging down along the trunk (see: Figure 11). Sometimes palms will stay productive even though they show signs of Ganoderma, but often they die within a year.

Goal

To minimise the spread of Ganoderma through a plantation

Standard

Figure 12: Ganoderma bracket

• Brackets (see: Figure 12) are taken from the infected palms and destroyed;
• Soil is mounted around the base of infected palms;
• Dead palms are removed from the plantation and burned;
• Remediation: Field is left without palms for at least 12 months after felling of old palms.

Equipment and materials

• Bush knife (to cut off the brackets)
• Chain saw
• Spade or digging machine

Timing

• Removing brackets: As soon as they are observed;
• Soil mounting: As soon as signs of Ganoderma infection are observed;
• Remediation: After felling, before replanting.

Frequency

Depends on the frequency and speed of new infections.

Labour time required

• Removal of brackets: A few minutes per palm;
• Soil piling: 30 minutes per palm;
• Cutting and removing palms: Several hours per palm, depending on the available equipment.

Who

Farmers and their families or hired labourers.

How

To control Ganoderma follow these steps:

Step 1.	During harvesting or other field activities look at the palms carefully and note any yellowing or dying of leaves, or the appearance of brackets on the trunks. In particular, look for the following: Several unopened new leaves (spear leaves) in the top of the crown; A ring of dead or dying leaves hanging around the trunk; General yellowing of the leaves; Small-looking canopy; Brackets forming on the trunk ,
Step 2.	If there are signs which might indicate Ganoderma, then check the trunk carefully at every harvesting round for signs of brackets. If brackets do not appear within a few weeks, then it is likely that they will not appear later on. If the palm has brackets, then these should be cut off, taken out of the plantation, and destroyed (burned).
Step 3.	To slow the progress of the disease in the palm, it can help to mount soil around the base of palms which show early signs of infection. To do this make a heap of soil up to 75 cm high and 50 cm wide around the trunk. The disease progress should slow down. Note: this option is labour-intensive and will probably not stop the disease in the end.
Step 4.	To prevent spreading of the disease from root to root, plantations often remove sick palms entirely. For smallholders without chain saws or heavy machines, removing the palms can be very labour-intensive, so it is up to each farmer to decide if he wants to do this or not. If the decision has been made to remove infected palms then follow these steps: Fell all the palms that are dead or have brackets; Cut the trunk into pieces; Remove all pieces that show disease symptoms (blackening in the inside of the trunk) from the plantation and burn them; Shred or cut the remaining pieces into smaller chips and leave those in the plantation to decompose. Note: If they are not cut into smaller pieces, they will become breeding sites for rhinoceros beetles! Dig out the palm bole (i.e. the part of the roots directly under the base) by making a hole at least 50 cm deep. Spread the soil equally around the hole. Remove the bole from the plantation and burn it. Leave the hole open or fill it with clean soil from the inter-row.

Note: When Ganoderma symptoms are observed, the palm has already been infected for quite some time. Therefore, even when taking the measures described above, the disease can still spread. There is still much that is unclear about the best way to deal with Ganoderma, even though it is a very common and destructive disease. The best time to prevent Ganoderma is at the replanting stage. Currently, it is recommended to remove all diseased palms and also the roots and the soil from a 2x2-meter hole of 1-meter deep, and to wait at least one year before planting any new oil palms. The new palms should be planted where previously the frond piles and harvesting paths were located, as far from the previous planting holes as possible.

Data recording

Every disease control activity should be recorded in a logbook as shown in the example below.

Date	Time	Location	Activity	Input type	Input amount	Input costs	Labour input		Labour costs
							People	Hours
16/01/13		Field 3	Removing Ganoderma brackets				1	4	40000

Acknowledgements

The material from Ganoderma is sourced from Smallholder Oil Palm Handbook and put together by Lotte Suzanne Woittiez (Wageningen Universit) and Haryono Sadikin, Sri Turhina, Hidayat Dani, Tri Purba Dukan, and Hans Smit (SNV) in August 2016. See Module 5: Pests and Diseases for more information.