Which factor on the list relates to the LD50 value as it pertains to pest kill efficiency?

• A. The pest developed resistance to the pesticide
• B. The LD50 of the pesticide is too low
• C. The rate of product applied was too high
• D. The restricted-entry interval was not followed

Answer: (B)

LD50 is the dose that kills 50% of the test pest population. A very low LD50 means the pesticide is highly toxic to pests, so effective kill can be achieved at smaller amounts. That direct link between how potent the chemical is (low LD50) and how well it kills pests at practical application rates is why this factor relates to pest kill efficiency. If pests develop resistance, you’d effectively need a higher dose (LD50 would rise), which isn’t about potency at a given dose. Applying too much product concerns application rate, not the inherent potency measured by LD50. And the restricted-entry interval relates to safety after application, not the pesticide’s kill power.