No abstract

The South American tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest in tomato crops. After having spread rapidly in the Mediterranean area since its first detection in 2006, it has recently become established in greenhouses in Western Europe. It was assumed that the low temperatures commonly associated with the winters in this area would prevent this exotic species from successful overwintering. However, the observed presence of T. absoluta at the start of the growing season in Belgium sparked a study on its potential to overwinter in Western Europe. In this study, the insect's cold hardiness and overwintering potential was assessed by determining: (1) the supercooling point (SCP) of larvae, pupae, and adults, (2) the lower lethal time (LT) for these stages at 0 and 5 A degrees C, and (3) the reproductive diapause incidence, as indicated by the reproductive performance of females reared at two temperatures (18 and 25 A degrees C) and two photoperiods [16:8 and 8:16 (L:D) h]. The mean SCP recorded for pupae (-16.7 A degrees C) was significantly higher than for adults (-17.8 A degrees C) and larvae (-18.2 A degrees C). Based on estimates of the LT adults demonstrated better cold hardiness than larvae and pupae at both 0 and 5 A degrees C with the median LT of adults averaging 17.9 and 27.2 days, respectively. No reproductive diapause was observed under the tested regimes. The results of this study indicate that T. absoluta is likely to successfully overwinter between two successive tomato crops in commercial greenhouses in Western Europe

BACKGROUND: Previous studies have indicated the control potential of entomopathogenic nematodes (EPNs) against Tuta absoluta. Here, the potential of Steinernema feltiae, S. carpocapsae and Heterorhabditis bacteriophora is studied when applied against larvae of T. absoluta inside leaf mines in tomato leaf discs by means of an automated spray boom. RESULTS:The studied EPN species were effective against all four larval instars of T. absoluta but caused higher mortality in the later instars (e.g. fourth instar: 77.1-97.4% mortality) than in the first instars (36.8-60.0% mortality). Overall, S. feltiae and S. carpocapsae yielded better results than H. bacteriophora. Steinernema carpocapsae and H. bacteriophora performed better at 25 ∘ C (causing 55.3 and 97.4% mortality respectively) than at 18 ∘ C (causing 12.5 and 34.2% mortality respectively), whereas S. feltiae caused 100% mortality at both temperatures. Under optimal spraying conditions and with the use of Addit and Silwet L-77 adjuvants, a reduced dosage of 6.8 infective juveniles (IJs) cm −2 yielded equally good control as a recommended dosage of 27.3 IJs cm −2 .CONCLUSION: Under laboratory conditions, S. feltiae and S. carpocapsae showed good potential against the larvae of T. absoluta inside tomato leaf mines. Results need to be confirmed in greenhouse experiments.

M. pygmaeus can cause economic damage to tomato fruits at densities common in practice. An infection of the plants with PepMV enhances fruit symptoms significantly. Interacting plant defence responses are most likely the key to explaining this, although confirmation is required. © 2015 Society of Chemical Industry.

No abstract

Over the last decade, the tomato russet mite, Aculops lycopersici, has become a major pest in tomato crops worldwide, both in open‐field and protected cultivation. Its minute size of 150 to 200 μm complicates early detection and monitoring in tomato crops. Passive dispersal occurs via air currents, crop management practices and commercial trade. Chemical control of Aculops lycopersici is difficult. Altered product use from broad spectrum pesticides towards selective acaricides, to meet integrated pest management (IPM) standards, has created better conditions for the rapid expansion of this specialized eriophyid mite. Moreover, practical implementation of promising natural enemies is challenging due to the complexity of biological control in tomato crops. Trichomes on tomato negatively affect arthropod natural enemies, but provide a refuge for the tomato russet mite. Despite the cosmopolitan nature of Aculops lycopersici, knowledge associated with IPM is limited and fragmented. This review describes fundamental biological data on Aculops lycopersici from the last 20 years and novel developments in the field of prevention, monitoring, chemical and biological control. The recent analysis of the genome sequence will be helpful in the development of a sustainable control strategy for Aculops lycopersici. © 2021 Society of Chemical Industry

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.

Rubber pest mites, Calacarus heveae and Tenuipalpus heveae, reach economic damage levels at the end of the rainy season and the beginning of the dry season in Brazil. Therefore, low humidity adaptation might be an important characteristic for predatory mites to successfully control pest organisms. This study determined the effect of the relative humidity (RH) levels of 30-100% on the hatching of larvae of Amblyseius acalyphus, Euseius citrifolius, Iphiseiodes zuluagai, Metaseiulus camelliae, Agistemus floridanus and Zetzellia malvinae at 25 +/- 0.5 degrees C. These predatory mites are common on rubber trees in the state of São Paulo and might be used for introduction in the major rubber tree production regions in the state of Mato Grosso. At 70% RH or higher, viability was 70% or higher for all species, indicating that their performance might be higher during the rainy season than during the dry season. Eggs of E. citrifolius and M. camelliae presented higher viability at the lower relative humidity levels than those of other species, indicating that these species might have higher chance to persist in the dry season. It is suggested that M. camelliae should be further evaluated for introduction in the state of Mato Grosso, considering that this mite is not yet present in that area.