Abstract
The current study was conducted to develop a cost-effective and reliable method to estimate population densities of 1st-instar bag worms, Oiketicus kirbyi (Guilding), in Costa Rican oil palm plantations. Total numbers of larvae per tree were correlated with numbers on 80, 160, 240, or all (320–360) folioles of all palm leaves. The r2 values of these correlations were used to assess the accuracy of population estimates obtained by sampling leaves in different positions within the palm crown or different numbers of folioles per leaf. Larvae were most abundant on apical and subapical foliolesof leavesin the upper palm crown. When a limited number of folioles per leaf (80, 160, or 240) was sampled, leaves in the upper crown provided the most accurate estimates of larval densities per tree. Decreasing accuracy of population estimates from upper to lower leaves resulted from increasing variability of larval proportions from upper to lower leaves. Larval populations of 2 other oil palm defoliators, Opsiphanes cassina (Felder), and Stenoma cecropia (Meyrick), are currently assessed by sampling leaf 17. Sampling O. kirbyi larvae on 160 foliolesof leaf 17, in the middle palm crown, may represent an acceptable compromise among cost-efficiency, reliability, and simultaneous assessments of several defoliatingcaterpillars. Reasonablyaccurate estimates of larvaldensities per area obtained in this study by sampling 1 palm per hectare should not be interpreted as a general recommendation for sample size, because the effect of population density on optimal sample size per hectare remains yet to be investigated.
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Claims 6
Claim · model-written summary
Bagworm larvae were most abundant on apical and subapical folioles in the upper palm crown.
- Taxon
- Oil Palmt0
- Organ / stage
- apical and subapical foliolesof leavesin the upper palm crowne0
- Interactor
- Oiketicus kirbyi (Guilding)
Oiketicus kirbyie1pest - Outcome
- Larvae were most abundante0
- Direction
- most abundante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Larvae were most abundant on apical and subapical foliolesof leavesin the upper palm crown”
e1“Oiketicus kirbyi (Guilding)”
t0“Oil Palm”
Claim · model-written summary
Upper crown leaves gave the most accurate density estimates with limited foliole sampling.
- Taxon
- Oil Palmt0
- Interactor
- Oiketicus kirbyi (Guilding)Oiketicus kirbyie1pest
- Outcome
- accurate estimates of larval densities per treee0
- Direction
- most accuratee0
- Value
- 80, 160, or 240e0
- Comparator
- upper crowne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When a limited number of folioles per leaf (80, 160, or 240) was sampled, leaves in the upper crown provided the most accurate estimates of larval densities per tree”
e1“Oiketicus kirbyi (Guilding)”
t0“Oil Palm”
Claim · model-written summary
Accuracy decreased from upper to lower leaves as larval proportions became more variable.
- Taxon
- Oil Palmt0
- Organ / stage
- upper to lower leavese0
- Interactor
- Oiketicus kirbyi (Guilding)Oiketicus kirbyie1pest
- Outcome
- accuracy of population estimatese0
- Direction
- Decreasinge0
- Qualifier
- increasing variability of larval proportionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Decreasing accuracy of population estimates from upper to lower leaves resulted from increasing variability of larval proportions from upper to lower leaves”
e1“Oiketicus kirbyi (Guilding)”
t0“Oil Palm”
Claim · model-written summary
Sampling 160 folioles on leaf 17 may balance cost, reliability and assessment of multiple defoliators.
- Taxon
- Oil Palmt0
- Treatment
- Sampling O. kirbyi larvae on 160 foliolesof leaf 17e0
- Interactor
- O. kirbyiOiketicus kirbyie0pest
- Outcome
- acceptable compromise among cost-efficiency, reliability, and simultaneous assessments of several defoliatingcaterpillarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sampling O. kirbyi larvae on 160 foliolesof leaf 17, in the middle palm crown, may represent an acceptable compromise among cost-efficiency, reliability, and simultaneous assessments of several defoliatingcaterpillars”
t0“Oil Palm”
Claim · model-written summary
Sampling one palm per hectare gave reasonably accurate estimates of larval density per area.
- Taxon
- Oil Palmt0
- Interactor
- Oiketicus kirbyi (Guilding)Oiketicus kirbyie1pest
- Outcome
- Reasonablyaccurate estimates of larvaldensities per areae0
- Value
- 1 palm per hectaree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Reasonablyaccurate estimates of larvaldensities per area obtained in this study by sampling 1 palm per hectare”
e1“Oiketicus kirbyi (Guilding)”
t0“Oil Palm”
Claim · model-written summary
The one-palm-per-hectare sample size should not be a general recommendation until density effects are investigated.
Verbatim
e0“should not be interpreted as a general recommendation for sample size, because the effect of population density on optimal sample size per hectare remains yet to be investigated”
e1“1 palm per hectare”
t0“Oil Palm”