Other Pest, Agri-crop

Golden Apple Snail (GAS) or Epikuhl. Local names: bisukol (Iloc.), kuhol (Tag.).

          Golden snail  is one of the delicacies enjoyed by farmers before. Now it is a recognized rice pest. It produces numerous pinkish egg masses  visibly seen on levees which usually hatch from 9 to 12 days. This pest is destructive during the early growth stage of rice plants 14 days from sowing to 20 days after transplanting.

          The pest feeds on the vegetative parts of young rice plants and could wipe out plants in a given area overnight.

Population of golden apple snail can be prevented by the following:

1. Handpick the golden snails and use these as animal feed.
2. Observe cleanliness and sanitation.
3. If cultural management is not feasible use molluscicide to control them. Drain water before spraying and always wear protective gear when using chemicals.

Rat Control

          Rats have been a persistent problem of rice growers, especially in areas near forests and uncultivated lands. They cause estimated yields losses ranging from 5-60%. Rats attack at all stages of rice growth but reach their peak during the maturity stage. Damage is greater during wet season. To control rats effectively, keep the rice fields clean and employ sustained baiting only when necessary. Make use of available rodenticides  in the agricultural supply and always follow the manufacturer’s instruction in its label.

Diseases and their Control

The most practical way to prevent the occurrence of diseases is to plant resistant varieties, practice good cultural management starting from the land preparation, and always remember to have at least 30 days planting breaks.

Viral Diseases

1. Tungro. The most destructive among virus diseases, this  usually occurs in a lowland ricefield. It is caused by virus which is transmitted from a diseased plant to a healthy one through the feeding activity by three leafhopper species: Nephotettix virescens, N. nigropictus and Resilia dosalis. Nephotettix virescens is the most destructive vector. Tungro occurs from seedling to booting stages (Figure 12). It is prevalent in the whole country except inBatanes during the wet season from July to November. Figure 13 presents the transmission cycle of rice tungro.
2. Yellow dwarf. The disease usually occurs sporadically in fields. Infection often takes place during the late stages of plant growth. The virus is transmitted by three species of leafhoppers: Nephotettix cincticeps, N. nigropictus and N. malayanus. Most leafhoppers acquire the virus by feeding on diseased plants for 1-3 hours. About half the infective individuals of the species can infect healthy plants within 1 hour feeding. Yellow dwarf is prevalent from seeding to booting stages.
3. Grassy stunt. This is prevalent in farms employing an overlapping rice cropping system. The virus may survive in the harvested rice stubbles. Generally, the disease is less severe when older plants are infected. The virus is transmitted from infected plants to healthy ones by the brown planthopper. The disease usually infects the rice plant during the seedling to booting stages.

Bacterial Diseases

1. Bacterial leaf blight. (Xanthomonas campestris). It is widespread in the country especially in areas with high rainfall and humidity. Infection starts at the tip of leaf margins and may cover the entire leaf blade. The bacterium enters the leaf through cuts or wounds and on the natural openings of the leaf. The systematic form of the disease called “kresek” usually occurs at seedling stage up to the dough stage. The form of the disease is known as “blight.” This is prevalent especially after typhoons.
2. Bacterial leaf streak. (Xanthomonas campestris pv. Oryziccola). This disease does not reduce yield if low rates of nitrogen are applied although it may lower yields of susceptible varieties. The disease may spread throughout the entire rice field by the action of rain and wind. It attacks the rice plant from tillering to dough stages. The disease is prevalent after typhoons.

Fungal Diseases

1. Rice blast. (Pyricularia oryzae). This is the most common disease of rice infecting plants at any stage of growth. Symptoms are most conspicuous on the leaves (leaf blast), nodes (nodal blast) and parts of the panicles (neck rot), and grain. The neck of the panicles becomes most vulnerable to attack during early emergence of the panicle. Lesions form at the neck causing the panicles to fall over.
             The disease development and severity is aggravated by high amount of quick acting fertilizers such as ammonium sulfate, cloudy skies with frequent rains and drizzle, and a relative humidity of 90% and above usually common during the months of November to February.
2. Cercospora leafspot (Sphaerulina oryzina Hara). The long axis of this spot is parallel with the veins of the leaf. This disease is also known as narrow brown spot. It seldom infects seedlings or grains. In susceptible varieties, the spot may be slightly wider in light, narrow centers. It causes harm by reducing the effective leaf area of the plant. The disease is favored by low nitrogen level in the soil.
3. Brown spot or Helminthosporium leaf spot (Helminthosporium oryzae). This disease is probably present in all rice producing areas. It infects  all stages of a rice plant. It is common in nutrient deficient soil and soils containing a large proportion of sand or peat.
4. Stem rot (Helminthosporium sigmoidium). Infection of the disease occurs near the water line usually at the maximum tillering stage up to the milk stage. Severely infected plants produce poor quality grains that are light and chalky.
5. Sheath blight (Rhizoctonia solani). The disease occurs during the heading stage to the milk stage. Sheath blight is destructive under highly humid and warm temperature and in areas where close planting and heavy fertilization are practiced.
6. Sheath rot (Sanocladium oryzae Sawada). The fungus is seedborne and infection takes place through the stomata and wounds. It attacks the leaf sheath enclosing young panicles when there is an injury which retards the emergence of the panicles. An abundant whitish powder growth may be found inside the infected sheath and the young panicle rot. The disease incidence is common with stemborer, planthopper and mite damage,  and application of high nitrogen.

               IMPORTANT THINGS TO REMEMBER

• Methods of controlling pest and diseases
• Cultural method
• Proper land preparation
• Plant at the same time with your neighboring farmers
• Clean culture
• Chemical method. Always read labels before use
• Biological method
• Introduction of friendly insects to suppress pests and diseases
• With the help of predators such as birds, snakes
• Use of resistant varieties
• Always be familiar with Insect pests/diseases, nature of attack and control measures

• The safety measures in handling chemical are the following:
• Store pesticides locked and out of reach of children
• Wear gloves when mixing pesticides
• Wear mask to prevent inhalation of pesticides. Always wash hands with soap after spraying
• Do not smoke or eat when using pesticides

• Consider the IPM to avoid wastage brought by unnecessary spraying of pesticides
• Use varieties resistant to pests prevalent in the locality. The use of resistant varieties is the first line of defense in pest management and is compatible with biological control. Change or rotate varieties every 2 - 4 cropping to disrupt insect pest and disease adaptation, thereby preventing build up of virulent pathogens and insect pests.
• Adopt a synchronous planting scheme after a fallow period in the locality.
• Conserve beneficial organisms. There are rich communities of beneficial organisms in the rice ecosystem in the absence of natural-enemy killing pesticides. The indiscriminate use of pesticides reduces biodiversity and disrupts the natural balance of insect pests and beneficial organisms. Conservation of these beneficial organisms is safe, economical, and permanent. For example, long-horned grasshopper feeds on the egg mass of stem borers while spiders feed on the nymphs and adults of leafhoppers and plant hoppers.

• Weeds are destructive, they reduce rice yield by competing for sunlight, moisture, and soil nutrients.
• Three types of weeds are grasses, sedges,
• . and broadleaves.
• The methods of controlling weeds are:

a.    Preventive method

b.   Physical/mechanical method

c.    Cultural method

d.   Chemical method

• Pointers for effective use of herbicide:

a.    Apply at the right time

b.   Use the right dosage

c.    Spray during fair weather

d.   Distribute spray solution accurately

Eradicate – to wipe out

Weeds - plants that grow  in places where they are not wanted

Grasses - weeds which have long narrow, two-ranked usually flat

              leaves with parallel veins and round stem

Sedges - similar to grasses but of three-ranked leaves, and

 with triangular solid stems

Broad-leaved weeds - dicotyledonous plants with broadleaves

Herbicides - chemical used to control and kill weeds

Insect pests - insects that are harmful to plants

Rodents – rats

Diseases – impairments on the normal health of the plant

Insecticides - chemicals used to control insects

Fungicides - chemicals used to control fungus

Molluscicide - chemical used to control golden  snails

Lesion - a well-marked but limited diseased area on the plants

Nocturnal insect - insect that feeds on plants during night time

Dead heart - dried youngest leaf of the plant during tillering stage

White head – dried, unfilled white panicle during heading stage

Symptoms -  observable characteristics of a diseased plant

PPE - personal protective  equipment