Binomial sampling plan for tomato russet mite (Aculopslycopersici (Tryon) (Acari: Eriophyidae) in protected tomato crops

Abstract

The tomato russet mite (TRM), Aculops lycopersici, is a worldwide pest of cultivated tomatoes. Currently, no effective biological control agents are available on the market. Therefore, chemical spray applications are required. Fast and reliable detection, monitoring and evaluation of interventions are a challenge, slowing down the development of an appropriate integrated pest management (IPM) strategy. This study describes a binomial sampling plan with the aim to reduce the efforts and costs for an accurate monitoring of A. lycopersici. Sampling was performed by taking pictures of the upper leaf surface with a smartphone through an attached magnification lens. A binomial sampling plan was developed based on the linear relationship between ln(mean TRM densities) and ln(−ln(1‐PT), where PT is the proportion of samples with more than T (tally threshold) mites. The minimum precision threshold of 0.30 was determined for the different models. A resampling for validation of sample plans (RVSP) programme with a fixed sample number was used for validation of the model on an independent data set. The binomial sampling plans were validated at tally thresholds of T = 9 and T = 15 with fixed sample sizes of 15, 20, 25 and 30. Precision levels were satisfying within a range of PT‐values from 0.29 to 0.97 for T = 15 at a fixed sample size of 20. This range was much smaller for T = 9, where the PT‐values range between 0.40 and 0.92 at the same sample size. A binomial sampling model with T = 9 with a fixed sample size of 15, which has the lowest time investment, is feasible for glasshouse tomato growers in practice. However, for the development of pest management programmes, a more intensive and more accurate binomial sampling plan with T = 15 and a sample size of minimum 20 is suggested.

Is the emerging mite pest Aculops lycopersici controllable? Global and genome‐based insights in its biology and management

“…In protected tomato cultivation, the ability of the mite to survive the period in between two cultivation cycles and transfer from a removed infested crop to a newly planted tomato crop, may allow early infestation of the crop. In many places around the world, the area of artificially lighted glasshouse crops has increased exponentially during recent years 8 . This has led to situations of year round production in tomato cultivation 8 .…”

“…In many places around the world, the area of artificially lighted glasshouse crops has increased exponentially during recent years 8 . This has led to situations of year round production in tomato cultivation 8 . A clean start of the new crop is of utmost importance but has become a challenge.…”

“…Populations often remain undetected for too long and once detected, the densities are frequently underestimated. Various efforts have been undertaken to develop efficient and accurate methods to make eriophyid sampling and population estimations easier 8,9,32 . Aculops lycopersici can be detected by measuring changes in volatile organic compounds (VOCs) emitted by the trichomes with a portable gas chromatograph 32 .…”

“…Aculops lycopersici feeds and reproduces on cultivated tomato until high population densities are reached and the plant suffers severe damage or dies 1 . The tomato russet mite has recently emerged as a serious pest problem in European glasshouse and open‐field tomatoes, for unclear reasons 2,4,8,9 . The basic morphology and biology of Aculops lycopersici has been described in detail by a range of authors in the mid‐20 th century 6,7,10 .…”

Genome streamlining in a minute herbivore that manipulates its host plant

“…Since the 1930s, the tomato russet mite A. lycopersici has been reported as a minor pest of cultivated tomato ( Solanum lycopersicum L.) worldwide ( Massee, 1937 ). For unknown reasons, it has emerged in recent years as a significant pest of tomatoes in European greenhouses ( Moerkens et al, 2018 ). While it is extremely small – only ~50 μm wide and 175 μm in length ( Figure 1a,b ) – it can reach high population densities ( Figure 1c ).…”