title: Spatial distribution and sequential sampling plans for Tuta absoluta (Lepidoptera: Gelechiidae) in greenhouse tomato crops.
abstract: BACKGROUND
  The within- and between-plant distribution of the tomato leafminer, Tuta absoluta (Meyrick), was investigated in order to define action thresholds based on leaf infestation and to propose enumerative and binomial sequential sampling plans for pest management applications in protected crops.
  
  
  RESULTS
  The pest spatial distribution was aggregated between plants, and median leaves were the most suitable sample to evaluate the pest density. Action thresholds of 36 and 48%, 43 and 56% and 60 and 73% infested leaves, corresponding to economic thresholds of 1 and 3% damaged fruits, were defined for tomato cultivars with big, medium and small fruits respectively. Green's method was a more suitable enumerative sampling plan as it required a lower sampling effort. Binomial sampling plans needed lower average sample sizes than enumerative plans to make a treatment decision, with probabilities of error of <0.10.
  
  
  CONCLUSIONS
  The enumerative sampling plan required 87 or 343 leaves to estimate the population density in extensive or intensive ecological studies respectively. Binomial plans would be more practical and efficient for control purposes, needing average sample sizes of 17, 20 and 14 leaves to take a pest management decision in order to avoid fruit damage higher than 1% in cultivars with big, medium and small fruits respectively.
authors.affiliation: Department of Agriculture, University of Sassari, Sassari, Italy.
authors.forename: Arturo
authors.initials: A
authors.lastname: Cocco
authors.affiliation: Institute of Ecosystem Study, National Research Council, Sassari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Serra
authors.affiliation: Department of Agriculture, University of Sassari, Sassari, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lentini
authors.affiliation: Department of Agriculture, University of Sassari, Sassari, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Deliperi
authors.affiliation: Department of Agriculture, University of Sassari, Sassari, Italy.
authors.forename: Gavino
authors.initials: G
authors.lastname: Delrio
mesh_terms: D000818:Animals; D016010:Binomial Distribution; D007814:Larva / Q000502:physiology; D018551:Solanum lycopersicum / Q000469:parasitology*; D009036:Moths / Q000502:physiology*; D010571:Pest Control / Q000379:methods* / Q000706:statistics & numerical data; D018515:Plant Leaves / Q000469:parasitology
keywords: Iwao's patchiness regression; Taylor's power law; binomial sampling; enumerative sampling; resampling validation; tomato leafminer