How to Control Sugarcane Borers? Detailed Explanation of Their Occurrence Patterns and Damage
Sugarcane borers, also known as sugarcane stem borers, are pests that occur relatively commonly and cause serious damage during sugarcane growth. So what are the occurrence patterns and damage of sugarcane borers? How to control them?
1. What are the occurrence patterns and damage of sugarcane borers?
The common borers in sugarcane fields are: the spotted borer, the striped borer, the yellow borer, the white borer, etc.
1. Occurrence patterns and damage of the spotted borer
(1) Occurrence patterns
This pest occurs 4 to 5 generations per year in Guangxi, with overlapping generations; the larvae pupate in the sugarcane stems, and overwintering larvae are often in the underground sugarcane stubble; eggs are mostly laid on the underside of green leaves in the middle and lower parts of sugarcane seedlings, arranged in 3-4 rows in a fish-scale pattern, with flat, oval eggs. The larval body has 5 longitudinal lines on its back.
(2) Damage status
In the early stage, the larvae bore into the stems of sugarcane seedlings to cause damage, resulting in dead heart seedlings, and can move to other plants to cause damage; in the later stage, they bore into the sugarcane stems to form borer-damaged nodes. There are two peak damage periods in a year: one from late March to mid-to-late April; the other from late May to late June, with the first peak period causing the most severe damage.
2. Occurrence patterns and damage of the striped borer
(1) Occurrence patterns
This pest occurs 4 to 5 generations per year in Guangxi; mature larvae often overwinter in leaf sheaths or sugarcane stems; eggs are mostly laid on the upper side of sugarcane leaves, arranged in double rows in a “” shape, with flat, oval eggs. The larval body has 4 longitudinal lines on its back.
(2) Damage status
Newly hatched larvae gather to damage the heart leaves, causing a layer of translucent irregular small spots after the sugarcane leaves unfold, called “mosaic leaves.” During the elongation stage, they invade from the sugarcane tip, forming dead tips and borer-damaged nodes, seriously affecting sugarcane stem growth.
3. Occurrence patterns and damage of the white borer
(1) Occurrence patterns
This pest occurs 4 to 5 generations per year in Guangxi; mature larvae overwinter in the sugarcane tips; eggs are mostly laid on the underside of sugarcane leaves, gathered into egg masses covered with orange-yellow fuzz.
(2) Damage status
Newly hatched larvae feed downward from the three-fork junction, and the damaged heart leaves, after unfolding, show rows of horizontal feeding holes. They bore downward to the growing point, causing dead hearts or dead tips. The damage peaks generally appear in early May, early June, late July, early September, and late October.
4. Occurrence patterns and damage of the yellow borer
(1) Occurrence patterns
This pest occurs 6 to 7 generations per year in Guangxi, with overlapping generations, causing damage year-round; eggs are laid singly, mostly on the old leaf sheaths at the base of sugarcane seedlings; mature larvae often pupate at the feeding sites. This pest prefers humid conditions, and the rainy season is conducive to its occurrence.
(2) Damage status
Newly hatched larvae invade from sugarcane buds or root bands, causing dead heart seedlings at the seedling stage; in the later stage, they invade from bud eyes, root bands and growth bands, forming bored buds and wind-broken stems. The larvae do not move to other plants to cause damage; in Guangxi, 6-7 peaks can be seen throughout the year, with large occurrences from March to June.
2. How to control sugarcane borers?
1. Eliminate overwintering sugarcane borers and reduce pest sources
When harvesting sugarcane, cut low with a small hoe, promptly remove residual stems, dead seedlings and dead leaves from the sugarcane field, and burn them on site in a centralized manner. Before the adult sugarcane borers emerge, cut off the autumn and winter shoots. In sugarcane fields where no ratoon crop is kept, plow up the sugarcane stumps and burn them or soak the field in water for 3 days to eliminate overwintering pest sources.
2. Chemical control
Based on factors such as the occurrence time of the first-generation sugarcane borers in previous years and temperature: the suitable control period for the first-generation sugarcane borers in 2017 was: late March and early-to-mid April (the specific time is subject to the local forecast time)
Specific operation:
3-5 days before the peak hatching period of the borers, use 20% Sushate emulsifiable concentrate or 51% emamectin benzoate · chlorpyrifos 100 ml/mu diluted with 40-45 kg of water and spray on the sugarcane plants, especially the heart leaves and stems, spraying them wet and thoroughly. Spray once about every 10 days, for two consecutive sprays, which can effectively control the occurrence of borer damage at the sugarcane seedling stage and mid-to-late stage.