The nurse sucker technique is an effective management tool. Its use, as with any technique used in banana growing, is obviously dependent on the costs versus benefits for individual plantations. Yield is forfeited by the nurse sucker technique both in lower bunch weight and the extra time between successive crops. However, the more uniform crops produced will reduce costs of production, and returns per carton can be higher if production is scheduled to coincide with high prices. There are four main benefits of nurse suckering.
Avoid expected production gluts
Whole production areas can be devastated by events such as severe cyclones. Without some form of management control, gluts can be expected when production recommences because about nine months production will be confined to a three month period.
Schedule more production for times of expected higher prices
Because of seasonal conditions, there is usually less production of fruit during the cooler part of the year (May through August), so growers can try to enhance returns by scheduling more fruit production during this period. The nurse sucker technique is one management procedure that can be used to bring back ratoon crops to these times of better prices.
Rejuvenate older ratoon blocks
After two or three ratoon crops, bunch harvest is commonly spread over six months instead of the two-three months in plant crops. This reduction in crop uniformity makes labour-intensive tasks (e.g. pest and disease control, bunch covering, and harvesting) more expensive to perform because more passes per crop must be made through the block.
These later ratoon crops also produce more fruit during the summer when market prices are lower and less profitable.
Nurse suckering is also particularly useful in breaking the leaf spot disease cycle in a block.
Rehabilitate wind-damaged blocks
Destructive winds probably represent the single major cause of yield loss in banana production. Apart from the initial losses, the effects of storms and cyclones are also felt long after the event. They contribute greatly to variability of harvest time in blocks where partial blow-downs occur and can invoke production at an undesirable time. The nurse sucker technique can be used to bring back crop uniformity and assist in control of crop timing.
How to create a nurse sucker
The steps for creating a nurse sucker are as follows:
- Select a sucker positioned in the row. (This sucker becomes the nurse sucker.)
- Harvest the bunch on the mother plant at the appropriate time. (Nurse suckering should only be done after the bunch has been harvested from the mother plant.)
- Ensure the nurse is at least 1.5 m tall to the throat and then cut down the nurse sucker and gouge out the growing point.
- Wait for the flush of suckers to develop from the nurse sucker.
- Wait approximately one month and then select one sucker that has developed on the nurse sucker.
By skipping a ratoon cycle, the technique is able to delay production of the next crop by about three months.
Figure 1. Steps for nurse suckering in bananas.
There are some variations to this procedure that largely centre around how the growing point of the nurse is dealt with. Cutting a wedge on the nurse no more than knee high and bending it over will effectively stimulate a flush of suckers on the nurse and is easier work than cutting and gouging. Another method is to leave the stem of the nurse standing and take out the growing point from the side with a desuckering gouge. In Central America, the growing point is killed by injecting Ethrel. While this approach is being investigated for northern Queensland, the use of Ethrel on bananas is currently not permitted in Australia. With the latter two approaches, the subsequent crop is bigger because of a greater boost from the leaf and pseudostem of the nurse.
When to nurse sucker
This depends on when in the year production is desired, the environment and set of crop management procedures. Production times at South Johnstone for three different nurse suckering times are shown in Table 1.
|Nurse cut down||Sucker set on nurse||Bunching||Harvest|
From experience, you will find out how much to vary these times to suit your district and particular set of crop management practices. For example, the slightly lower temperatures at Cardwell would mean that you need to start cutting down the nurse earlier to achieve harvest at a comparable time. Higher plant densities and water/nutrient stresses are examples of crop management that would delay development. Also, there will be variation in timings of harvest from year to year, depending on the weather, particularly how cold of a winter is experienced.