Pesticide Application in a Rice Farm in

Sablayan, Occ. Mindoro

CHEM 185 CASE STUDYMangao, ArnoldusRamos, Ana Rose

FARM PROFILELOCATION: San Vicente, Sablayan, Occ. MindoroCROP PLANTED: Rice

CHARACTERISTICS:• Three cropping per year• Conventional Farming• Irrigated

FARM PROFILE

Problems and its extentPresence of plant-eating mollusk

Presence of grasses that compete with the crop

No significant effect to yield since these problems are addressed

Pesticide Being Used• MOLLUSCICIDE

Visocol WP 50

• HERBICIDENomineeTopshoot

Molluscide: Visocol wp 50• CHEMISTRY• Main ingredient: Niclosamide• MOA: inhibits glucose uptake and oxidative phosphorylation

O

NH

OH

N+

O

O-Cl

Cl

5-Chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide

Molluscide: Visocol wp 50Environmental Fate

• Degrades rapidly in natural water and sediment systems• Depends on microbial activity• Soil mobility: slow to medium (0-25 cm, depends on soil type and

pH)• Degrades rapidly with UV (photolysis)• Does not affect

Cost, effectivity and application• COST• Php 800 per hectare

• APPLICATION• Before direct seeding or transplanting• Applied early in the morning or late in the afternoon

• EFFECTIVITY• Kills almost all of the snails

Herbicide 1: NomineeNa+

O O-

ON

N

O

O O

N

N O

O

sodium 2,6-bis((4,6-dimethoxypyrimidin-2-yl)oxy)benzoateChemical Formula: C19H17N4NaO8

Molecular Weight: 452.35

• CHEMISTRY• Main ingredient: Bispyribac-Sodium• MOA: inhibits acetolactate synthase

(ALS)

• a selective post-emergence herbicide to be applied in rice in order to control annual grasses and broad-leaved weeds (including Echinochloa spp., Cyperaceae etc.)

Herbicide 1: NomineeEnvironmental Fate• Bispyribac sodium underwent a moderate degradation

when exposed to sunlight• has a log Kow of -1.03 and thus it is unlikely to

bioaccumulate in the aquatic organisms• dissipated readily under aerobic soil conditions with a

half-life of 18.6-19.1 days in one soil.• is classified as being of low to high mobility depending

on soil type

Cost, effectivity and application• COST

• Php 1500/ha

• APPLICATION• a selective post-emergence herbicide; best results, apply NOMINEE only when both, crop and

weeds are actively growing; drain field to expose weeds.

• EFFECTIVITY• displays excellent activity against emerged weeds, but has almost no pre-emergent activity

and will therefore not control weeds that germinate after application.

• SELECTIVITY• Nominee does not have phytotoxic effects on rice provided dose rate and application

conditions are respected.

Herbicide 2: TopShot• CHEMISTRY• Main ingredient: Metsulfuron Methyl• MOA: inhibits cell division in the shoots and roots of the plant

• A sulfonylurea compound used as a selective pre- and postemergence herbicide for broadleaf weeds and some annual grasses

O

O

S

O

ONH

O

NH

N

N

N

O

methyl 2-(N-((4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoyl)sulfamoyl)benzoateChemical Formula: C14H15N5O6S

Molecular Weight: 381.36

Herbicide: TopShot• Environmental Fate

• The breakdown in soils is largely dependant on soil temperature, moisture content, and pH.

• degrade faster under acidic conditions, and in soils with higher moisture content and higher temperature

• It is rapidly taken up by plants at the roots and on foliage. The chemical is translocated throughout the plant, but is not persistent.

Cost, effectivity and application• COST

• APPLICATION• Apply at the time where weeds are actively growing

• EFFECTIVITY• works through the leaves and roots of the weeds, works rapidly after it is

taken up by the plant