Chemical control of mealybugs on pineapples
2019
Araya, M.
The mealybug Dysmicoccus brevipes is frequently found in Costa Rican pineapple plantations threatening the crop because of its association with the devastating disease known as pineapple mealybug wilt (PMW) caused by virus. An experiment in a randomized complete block design was conducted to determine an effective Nemacur® 40EC (fenamiphos) concentration for its control. Increasing rates tested were: 0, 4, 6, 8, and 10 L ha(‑1) in 2,000 L ha(‑1) of water with five repetitions. With exception of the untreated control (P=0.8654) mealybug mortality was significant (P<0.0001) 15 days after product application in all treatments. An increasing linear effect (P<0.0001) on mealybug mortality was observed as concentration increased. For every litre increase in product, the percentage of mortality increased an average of 6.7%. The highest mortality (78%) was observed in plants treated with 10 L ha(‑1) surpassing (P=0.0252) the control achieved with 4, 6 and 8 L. Since the mortality in the untreated control was so low (2%), the efficacy on mealybug control was close to the mortality rate. The recommended quantity was 10 L ha‑1 of Nemacur® 40EC with a biological efficacy of 78% 15 days after application.
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