Chemical Pesticide: Hapazard use, Residual effect, Secondary pest outbreak & Environmental impact

Chemical Pesticide & Its Serious Hazard


Agriculture nowadays is developing at higher rate than in old ages. Among the different sectors of agriculture, vegetable cultivation has improved rapidly at present where off- seasonal vegetable cultivation has developed as new dimension in cultivation sector. As it has higher profit than other sector, farmers are using pesticide randomly for higher profit. Generally, pesticide use per hector was only 142 grams by Nepali farmers in recent past has now increased to 1450 grams / hector which reflects most of the things itself.

Selection of highly toxic pesticide, application at higher rate than recommended and using higher amount without knowing the use of high dose, application of expired quality less pesticide, no adoption of waiting period for crop harvest etc. like situation has arisen serious risk in consumer health and even the producing farmers which are being reported in governmental studies. Lack of awareness, no consciousness and haphazard use of pesticide are causing misuse of pesticide in Nepal which are making vegetable very toxic with residual effect and fruits which are consumed without cooking due to pesticide residue even may cause death to the person having it.  Government only suggest not to apply pesticide without any alternative method to them. Obligation to apply pesticide is curse to farmers.

Areas like Pachkhal on studying, no households are found which do not apply pesticide. Nowadays, pesticide application and vegetable cultivation are similar to each other. Though on registering every pesticide, they provide the truthful label of it, on selling those products from retailers to farmers, such label is not attached with it. If such truthful label is attached to pesticide, farmers may have extra information about pesticide hazard and application technique. Ministry of Agriculture is not supervising this activity of retailers not attaching label along with pesticide. Farmers do not get information hence; government is making huge mistake in this case.

The major chemical pesticide effects are given below: –

False Pesticide:

False pesticide does not mean they are not pesticide but they do not contain the active ingredient (a.i.) pesticide amount according to their labeling. According to the governmental reports of 2065 and successive, among the 12 samples of pesticide examined thoroughly, only 2 sample contains pesticide (a.i.) according to label (+ to – 5%) whereas other contain very less amount that stated.

Pesticide Labelled a.i. Actual present
Doom-76 765 575
Cyperin 10 105 57.75
Anu M 45 755 885

Such false labelled pesticides are actually serious to use.

Human Health:

Though pesticides are sold in name of medicine they actually are poison. But due to lack of adequate awareness safety measures to be taken are not practiced to their level. Laborers during production, storage, transportation, wholeseller, retailers and farmers who use to apply them and eventually the consumers who consume those products are affected prey by those pesticides. Due to poverty and lack of awareness, costumes like apron, gloves, glasses, boots which are to be worn during spraying of pesticides are not in use or practice. Farmers are more likely to be susceptible to effect of pesticide during spraying, respiring in toxic air, weeding and harvesting in same field. Short term to long term effect will eventually cause to farmers like cancer and other respiratory problems by pesticide and to the consumers too.

Secondary pest outbreak:

Many examples are there where after application of pesticide, secondary pest outbreak. After application of pesticide to control rice ear head bug, brown plant hopper get outburst in epidemic way and cause serious damage. Similarly, farmers of Hemja kaski on applying pesticide (Cypermethrin) to control Citrus Green stink bug; red scale insect covers the whole mandarian tree. The insect disappears only after 2 years after stopping the pesticide application.

 Loss of Natural Predator:

If pesticide use is limited, natural pesticide will grow in abundant number and control the epidemic outbreak of harmful insects. Brown plant hopper is predated by insects of anagras species, tomato fruit borer is parasitized by trichogramma, scale insect by parasite aphaitis. On applying pesticide, it causes loss of natural predator and only harmful insect will survive which cause serious damage.

Pesticide resistant pest:

Pesticide resistant is phenomenon developed in long term on application of same nature of pesticide in the same crop in same field. Studies show, tomato fruit borer in syangja develop 56 times resistant, cotton bollworm of Nepalgunj develop 106 times resistant to Cypermethrin. It means that, if pest were killed by 1 ml of cypermethrin in 1 liter of water, now it requires 56 ml per liter in syanjga and 106 ml per liter in Nepalgunj to kill the insects. This is pesticide resistant. If this scenario occurs such insects will be impossible to control recently.

Loss of Honey Bee:

Along with development of modern agriculture, application of pesticide in different places has cause loss of honey bee naturally present and those which are cultured artificially too. Bees which travel long distance to collect pollen and help in pollination come in contact with toxic pesticide and died immediately which is causing serious problem in declining bee population. Farmer of Sinja valley of Jumla complain the sparse population of honey bee is due to pesticide use in those areas. It means even non developed part of country is using pesticide and causing problem all over the country.    

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