Pest Management
KEY CHECK 7:
NO SIGNIFICANT YIELD LOSS
DUE TO PESTS.
Knowing how the rice crop interacts with biotic factors and the agroecosystem, and correctly identifying pests and applying ecologically sound management strategies can help prevent significant yield loss. They can also promote high-quality grains.
ASSESSMENT OF KEY CHECK
No significant yield loss due to damages caused by insect pests, diseases, weeds, rats, snails, and birds. Such loss occurs when one or more pests inflict damage.
Check Tables 1-3 for practical assessment of pest damages.
Table 1. Insect pest level associated with significant yield loss (for 120-day-maturing variety).
Growth stage | Stem borer (SB) | Rice black bug (RBB) | Brown planthopper (BPH) / Whitebacked planthopper (WBPH) | Rice bug (RB) |
---|---|---|---|---|
Nursery/ Seedbed | ≥ 5 egg masses/㎡ | negligible | negligible | negligible |
Early tillering | ≥30% deadheart | ≥10 nymphs or adults/ hill; > 20% deadheart/ bugburn |
≥25 all stages of insects/hill | negligible |
Mid to max tillering/ Early panicle initiation (EPI) | ≥1 egg mass/㎡ | ≥20 nymphs or adults/ hill; ≥ 30% deadheart/ bugburn |
≥50 all stages of insects/hill | negligible |
Flowering | ≥20% whitehead | ≥20 nymphs or adults/ hill; >20 whitehead |
≥50 all stages of insects/hill | negligible |
Milk | ≥20% whitehead | ≥20 nymphs or adults/ hill; ≥20 whitehead |
>100 all stages of insects/hill | >5 nymphs and adults/㎡ |
Grainfilling | >20% whitehead | >20 nymphs or adults/ hill; ≥20 whitehead |
>100 all stages of insects/hill | >10 nymphs and adults/㎡ |
Maturity | ≥20% whitehead | ≥20% whitehead | ≥100 all stages of insects/hill | tolerable |
Insect pests are monitored in the early morning (5:00-7:00AM) or late afternoon(5:00PM). Other pests are usually monitored in the late afternoon.
Table 2. Disease level associated with significant yield loss (for 120-day- maturing variety).
Growth stage | Rice blast (leaf, neck, panicle) | Sheath blight (ShB) | Bacterial leaf blight (BLB) | Rice tungro disease (RTD) |
---|---|---|---|---|
Nursery/ Seedbed | ≥20% of seedbed with leaf blast | none to negligible | negligible | none |
Early tillering | ≥20% of field with RTD | |||
Mid to max tillering/ Early panicle initiation (EPI) | ≥30% of field with leaf blast | ≥40% of field with ShB | ≥30% of field with BLB and undeveloped spikelets | >40% of field with RTD |
Flowering | ≥10% of field with neck blast | ≥30% of field with BLB on flag leaf | tolerable | |
Milk | ≥10% of field with panicle blast | ≥30% of field with BLB and undeveloped spikelets | ||
Grainfilling | ≥40% of field with ShB and ≥10% unfilled grains | |||
Maturity |
Table 3. Weed, rat, snail, and bird infestation level associated with significant yield loss.
Weeds | Rats | Snails | Birds | |
---|---|---|---|---|
Significant yield loss | ≥ 5% of the area has weed cover at 0-40 DAS (DWSR), or >10% at 15-40 DAT (TPR) | ≥ 5% of the area has damaged tillers from maximum tillering to maturity | ≥ 10% of the area has missing or snaildamaged hills at 14 DAT or DAS | ≥ 5% of the area has damaged panicles |
RECOMMENDATIONS TO ACHIEVE KEY CHECK
Change or rotate varieties every 2-4 croppings.
2. Practice synchronous planting after a 30-day rest period (see Key Check 3).
3. Conduct regular field-monitoring from the early stage of crop growth onwards to identify potential pests at their initial stage of development. Preventive disease management options can be applied before it spreads and reaches intolerable levels. For insect pests, preventive management options such as use of resistant varieties and synchronous planting are preferred. Insecticide application is a corrective measure to be used as a last resort when all cultural, biological, and physical control measures fail.
4. Let the many beneficial organisms thrive in the rice ecosystem. Such organisms regulate pest populations. The indiscriminate use of pesticides reduces biodiversity and disrupts the natural balance of insect pests and beneficial organisms. Conserving these organisms is economical and permanent.
For example, long-horned grasshoppers feed on the egg masses of stemborers while spiders feed on the nymphs and adults of leaf and planthoppers.
Table 4. Management options for common rice pests
Pest/disease | Management options |
---|---|
Insect pests and diseases | Do not spray against defoliators within 30 DAT or 40 DAS. Diagnose diseases correctly, and practice field sanitation and synchronous planting after a rest period. |
Weeds |
|
Rats | Practice timely, integrated, and sustained communitywide control. Fill rat burrows with soil and water. Practice sanitation. |
Invasive Apple Snails also known as Golden Apple Snails (GAS) |
|
Birds | Scaring them away is the most practical approach to managing birds. |
MATERIALS
Handouts
Learning Modules
Audio Clips