BY CHRISTINE AWOR
Silkworms are one species of worms that are delicate and any mishandling can frustrate the entire process. Since ancient times, silk has been a valued commodity, which is obtained through silkworm rearing.
Silk is a versatile material with remarkable softness, strength, durability, elasticity, and absorbency. It is used in clothing, surgical sutures, bedding, parachutes and many other purposes.
Sericulture, which is the rearing/keeping of silkworms for silk harvest is a very profitable business on the global market, however, its success can be put short with the infection of just one silkworm
Sericulture industry has uplifted the social and economic livelihoods of people across the world by boosting textile industry which is key in plummeting unemployment in developing countries.
Livelihood and social improvement achieved through employment opportunities, income generation, economic development, ecological and environmental values, agriculture integration and environment protection.
In a bid to commercialize Sericulture, prevention of silkworm diseases is the only way to change it into a sustainable activity and to achieve all these visions.
According to Researchers From Tropical Institute Of Development Innovations Which is a leading implementer of Sericulture Project In Uganda advise that, a Sericulture farmer has to maintain good hygiene to prevent silkworm infections and diseases like Grassarie and muscardine from attacking the worms which are the commonest in Uganda
Grasserie
The viral disease is a viral disease of silkworm caused due to the presence of high temperatures and high humidity in the rearing house coupled with feeding of low quality mulberry leaves.
The milky fluid released by infected larvae contaminates the rearing house and appliances.
Symptoms
It is a highly infectious disease which is difficult to detect in the early stages of infection. At times the microscopic examination reveals presence of polyhedral bodies.
As the disease advances, the larvae lose appetite and skin becomes shiny before molting.
Control And Prevention measures
Rare under clean and hygienic condition, thorough disinfection of rearing room, appliances and surrounding, ensure proper disinfection of egg surface, incubate eggs under hygienic condition, avoid touching with hands, provide suitable and timely feed during rearing, maintain proper spacing and adequate ventilation, pick out diseased weak and Injured larvae and destroy them properly and finally apply bed disinfectants as per recommended schedule and quantity.
Muscardine
Muscardine is a fungal disease in silkworm.Various types of muscardine diseases have been reported i.e white,green,yellow etc
Apart from white Muscardine which is caused by fungus, Beauveria Bassiana the disease is caused due to body contamination by the fungus.
The fungus grows well under low temperatures.
Symptoms
The larva loses appetite, becomes sluggish ,ceases to move and finally die.
The dead larva becomes harder and mummified and the whole dead body becomes dead chalky White.
Causes.
High temperature and RH,poor ventilation,poor sanitation, improper bed cleaning, feeding of wet leaves, accumulation of feces, feeding of contaminated leaves, overcrowding of worms.
Control Measures
Effective disinfection of rearing house/appliances
Avoid overcrowding
Maintain optimum temperatures and relative humidity
Avoid feeding diseased and contaminated leaf
Collect diseased worms and destroy
Apply bleaching powder and lime at 1:9 ratio
Proper bed cleaning
Proper sanitation and hygiene
Mulberry sole food for silkworms equally needs utmost attention because its performance automatically affects the performance of silkworms, at the end of the rearing cycle. According to Researchers from TRIDI ,a major factor determining the productivity and profitability in Sericulture is the yield of Mulberry.
Maximization of mulberry leaf yield per unit area leads to realization of two most important objectives namely increased cocoon production per acre and reduced costs of production. Some of the mulberry leaf diseases includes leaf spot, leaf rust and powdery mildew caused by fungi significantly reduce the leaf quality and its yield.
They according to the research, also deplete the nutritional value of the leaves through reduction of proteins,sugars, chlorophyll and moisture content so proper disease management is a very key prerequisite for successful silkworm rearing.
1.Leaf Spot
The diseased leaves have a number of circular irregular dark brown spots of various sizes with clear boundaries and white centers.Leaves become yellow and wither off as disease becomes severe.More common in rainy seasons
Control
Spray 0.2%Bavistin (carbendazim 50% WP) solutions on the leaves.
2.Powdery mildew
Grey powder appears as whitish patches and quickly covers the entire surface of the leaves.It is found on the underside of the leaves.
Control
Spraying Mancozeb solution on the leaves
3.Leaf Rust
Leaf rust is caused by Cerotelium fici. The disease is prevalent during cold rainy seasons. It starts progressing 45-50 days after pruning and becomes severe by 70 days after pruning. This disease reduces yield by up to 10-15%.
Symptoms
Circular pinhead sized brown eruptive lesions appear on lower side of the leaves.later,the leaves become yellow and withers.
Silkworms are vital Sole productive insect species reared and exploited globally to boost the sericulture industry, but these worms are very delicate and need utmost attention right from their hatching to their cocooning stages, for a successful sericulture business
Compiled By Christine Awor, Public Relations Officer(P.R.O) TRIDI
