Question

The ETL for insect vectors in pest management is:
(A) 0%
(B) 0 to 0.5 %
(C) 1.0 to 1.5 %
(D) 2.0 to 2.5 %
Choose the correct answer from the options given below:

• (A) and (B) only
• (A) and (C) only
• (B) and (C) only
• (C) and (D) only

Hint:

ETL for vectors is typically 10x lower than for non-vector pests of the same crop.

Answer 1

The Correct Option is D

ETL (Economic Threshold Level) for vectors:
Disease vectors: 1
1.5% (C)
Severe outbreak vectors: 2
2.5% (D)
Lower thresholds than non
vector pests due to disease transmission risk
Zero tolerance not practical in field conditions

Answer 2

Alternate approach - reason from IPM principles rather than recalling exact figures:
An Economic Threshold Level (ETL) of exactly 0% is not practically achievable in the field, since it would demand total absence of the pest, so option (A) can be discarded outright.
Because insect vectors transmit disease, even a very low population can cause disproportionate crop loss through disease spread, so the acceptable threshold has to be kept much lower than for ordinary chewing or sucking pests - this rules out an unrealistically narrow single band being used alone.
Field-recommended values place the ETL for general vector management around 1.0 to 1.5%, rising to about 2.0 to 2.5% for conditions bordering on severe outbreak risk.
Since both of these ranges are recognised together in practice, the option pairing (C) and (D) is the one consistent with standard IPM guidelines.