Date Palm Mite Research Articles

Life history of the two predacious mites species, Amblyseius swirskii, and Neoseiulus cucumeris (Acari: Phytoseiidae), as biological control agents of the date palm mite, Oligonychus afrasiaticus (Acari: Tetranychidae).

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of dates in the Middle East and North Africa, inflicting severe economic damage if not controlled early. As predaceous mites are known to be potential biocontrol agents against several pests, so predation capacity, life table, reproduction, and survival of Amblyseius swirskii Athias-Henriot and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), collected from date palm farms in Qassim Saudi Arabia, were studied under laboratory conditions (25 °C, 30 °C, 35 °C and 50 ± 5% RH) against all motile stages of O. afrasiaticus. For both predators, mean developmental time, oviposition period, and longevity were inversely related to temperature from 25 to 35 °C. Various parameters were studied for A. swirskii and N. cucumeris at 25 °C, 30 °C and 35 °C, i.e. the female developmental time, 9.37, 7.29, 5.56, and 10.67, 8.38, 6.45 d; oviposition period, 19.77, 16.18, 13.94 and 15.90, 13.84, 10.64 d; longevity, 29.39, 24.79, 20.64 and 25.42, 21.94, 17.39 d; fecundity, 31.91, 37.10, 42.16 and 21.75, 26.84, 30.56 eggs per female, respectively. The maximum daily predation rate for both the predators was recorded at 35 °C during the oviposition period. The total predation of A. swirskii and N. cucumeris female was 370.86, 387.54, 405.83, 232.14, 263.32, 248.85 preys at 25 °C, 30 °C and 35 °C respectively. The maximum reproduction rate of A. swirskii and N. cucumeris (3.02, 2.87 eggs/♀/day) was recorded at 35 °C while the minimum (2.00, 1.36 eggs/♀/day) was recorded at 25 °C. The life table parameters were estimated as net reproductive rate (Ro) 21.68, 25.94, 29.52 and 18.95, 20.25, 22.78; the mean generation time (T) 24.92, 21.82, 18.24 and 26.30, 23.60, 20.56 d; the intrinsic rate of increase (rm) 0.181, 0.232, 0.248 and 0.170, 0.185, 0.196; the finite rate of increase (λ) 1.365, 1.551, 1.706 and 1.126, 1.324, 1.428 for A. swirskii and N. cucumeris at 25 °C, 30 °C and 35 °C respectively. The results of this study suggested that the two phytoseiid species are promising biological control agents of O. afrasiaticus at a wide range of temperatures.

Effectiveness of Nanoparticle-Based Treatments in Controlling Oligonychus afrasiaticus (McGregor) (Acari Tetranchidae) Infestation in Date Palm Trees

Date palm mite Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) infestations pose a significant threat to date palm plantations, leading to reduced crop yield and economic losses. Nanoparticle-based strategies have emerged as a promising approach for controlling mite populations due to their unique physicochemical properties and environmentally friendly nature. In this study, we investigated the impact of three different nanoparticle types, namely silver, silica, and sulphur, on the mortality rate of date palm mites at different life stages (larvae, nymphs, and adults). The experiments were conducted at various concentrations and time intervals to assess the efficacy of the treatments. The results revealed significant variations in the effectiveness of the nanoparticle types, with nanosulphur demonstrating the highest mortality rate (45.576%) followed by silica (38.587%) and silver nanoparticles (34.957%). Furthermore, the results indicated that adult mites were more susceptible to nanoparticle-induced mortality compared to larvae and nymphs. The concentration-dependent response showed that higher nanoparticle concentrations led to greater mite mortality, with the highest concentration (500 ppm) resulting in an impressive mortality rate of 55.163%. Time-dependent studies demonstrated a progressive increase in mortality rates over 48 hours, reaching 46.017% at the endpoint. These findings provide valuable insights into the differential susceptibility of date palm mite life stages to nanoparticle treatments and underscore the importance of considering both nanoparticle type and concentration for effective control of date palm mites. This knowledge contributes to the development of targeted nanoparticle-based strategies for mitigating date palm mite infestations and preserving the productivity of date palm plantations. This study contributes valuable insights into the potential use of nanoparticle-based treatments for managing O. afrasiaticus infestations in date palm trees.

Does the sampling of date palm fruits help in early detection of date palm mite, Oligonychus afrasiaticus (Acari: Tetranychidae)?

Early pest detection in an agroecosystem is desired for efficient pest management. A proper sampling plan is thus required with adequate sampling units and a small sample size. The date palm mite, Oligonychus afrasiaticus, is a severe pest of date fruits and its early detection is most needed. The present research aimed to identify whether a certain bunch direction or strand position of date fruit bunches could help in the early detection of date palm mite. The research was conducted in two climatic regions of Saudi Arabia, on six date palm cultivars and during four fruiting seasons. The date palm mite population dynamics data were collected from four bunch directions and three strand positions. For early pest detection, the population estimation started from the first appearance of the mite on the fruit bunches in each season, continuing till the first 3 weeks. The results depicted a clumped distribution of date palm mite in all bunch directions and strand positions. There was no significant difference in the mean date palm mite population, neither among three-strand positions nor among the four bunch directions. The mean population over the weeks showed that date palm mite almost equally infested the fruit bunches from all four directions and increased with non-significant differences. It is suggested that the plant parts basally adjacent to fruit bunches should be focused on the early detection of date palm mite.

Development and Validation of Innovative Machine Learning Models for Predicting Date Palm Mite Infestation on Fruits

The date palm mite (DPM), Oligonychus afrasiaticus (McGregor), is a key pest of unripe date fruits. The detection of this mite depends largely on the visual observations of the webs it produces on the green fruits. One of the most important problems of DPM control is the lack of an accurate decision-making approach for monitoring and predicting infestation on date fruits. Therefore, this study aimed to develop, evaluate, and validate prediction models for DPM infestation on fruits based on meteorological variables (temperature, relative humidity, wind speed, and solar radiation) and the physicochemical properties of date fruits (weight, firmness, moisture content, total soluble solids, total sugar, and tannin content) using two machine learning (ML) algorithms, i.e., linear regression (LR) and decision forest regression (DFR). The meteorological variables data in the study area were acquired using an IoT-based weather station. The physicochemical properties of two popular date palm cultivars, i.e., Khalas and Barhee, were analyzed at different fruit development stages. The development and performance of the LR and DFR prediction models were implemented using Microsoft Azure ML. The evaluation of the developed models indicated that the DFR was more accurate than the LR model in predicting the DPM based on the input variables, i.e., meteorological variables (R2 = 0.842), physicochemical properties variables (R2 = 0.895), and the combination of both meteorological and the physicochemical properties variables (R2 = 0.921). Accordingly, the developed DFR model was deployed as a fully functional prediction web service into the Azure cloud platform and the Excel add-ins. The validation of the deployed DFR model showed that it was able to predict the DPM count on date palm fruits based on the combination of meteorological and physicochemical properties variables (R2 = 0.918). The deployed DFR model by the web service of Azure Ml studio enhanced the prediction of the DPM count on the date fruits as a fast and easy-to-use approach. These findings demonstrated that the DFR model using Azure Ml Studio integrated into the Azure platform can be a powerful tool in integrated DPM management.

Evaluation under Laboratory Conditions of the Efficacy of Four Extracts of Spontaneous Plants from the Mzab Valley (Algeria) against the Date Palm Mite (Oligonychus afrasiaticus)

Trials were conducted to test the hydrosols of 4 spontaneous plants on the date palm mite, Oligonychus afrasiaticus, a key pest of date palm in Algeria. Extracts from those plants (basil, harmel, colocynth and hyssop) tested against date palm mite showed promising results. The quantities of essential oils extracted from the 4 plants were extremely low, that is why only hydrosols were used. The results obtained change depending on the number of sprays and the reading time after treatment. The hyssop extract caused a high mortality rate of 91%, followed by colocynth and basil extracts with average mortality rates of 64% and 62%, respectively. The lowest mortality rate, 6%, occurred when applying harmel extract.

Phenology and abundance of date palm mite Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) in Riyadh, Saudi Arabia.

In the present study, we evaluated the effect of management practices, fruit season, host habitats (young and old fronds, date fruits and grasses), and temperature on the phenology and abundance of the date palm mite (DPM). The study was conducted in two date palm orchards (two plots each): a managed and an unmanaged plot. The phenology of DPM was assessed based on adult cumulative mite days (ACMDs), while mean mite density was used to assess the mite abundance on different host habitats. The ACMDs and mean mite density were significantly different between managed and unmanaged plots on different host habitats in both fruiting and off-seasons. The date fruits had highest ACMDs during fruiting season. While young fronds had significantly higher ACMDs than on old fronds an grasses during both seasons in both plots.. The temperature and season type significantly affected the mean density of DPM eggs and adults. There was a significant effect of host habitats mean density of DPM eggs and immatures. Based on the adult phenology and abundance of DPM, the mite overwinters in young fronds and aerial offshoots of infested date palm trees. These overwintering DPM caused the seasonal date fruit infestation, each year. Additionally, different phytophagous and predatory mites, which co-occur with DPM, and were found on different host habitats affected the phenology and abundance of DPM. Moreover, the change in DPM body color was related to the host habitat that they fed in. Exceptionally, the brown color of females collected during the winter season could be due to physiological changes due to low temperature. In DPM males collected from different host habitats throughout the study, some morphological variations in the width of the knob, height of the hook, and the angle between the knob axis and dorsal margin of the shaft were also recorded. The results of this study suggest that young fronds and grasses are the suitable sites for DPM survival and overwintering. Hence, the management practices, early in the fruit season and/or during off fruit winter months, should be directed towards these habitats. These could provide efficient reduction in seasonal infestation of DPM.

Two new life types and assessment of web-associated behavioral characteristics of some Oligonychus species on various host plants.

The webbing life type of three spider mite species of the genus Oligonychus was studied based on web-associated behavioral characteristics. All tested Oligonychus species-viz., avocado brown mite, Oligonychus punicae (Hirst), date palm mite, Oligonychus afrasiaticus (McGregor), and banks grass mite, Oligonychus pratensis (Banks)-exhibited a complicated-web (CW) life type on various host plants. A new life type, 'CW-c,' was documented for O. punicae on the adaxial leaf side of Conocarpus erectus L. (Combretaceae). The weaving pattern with guy ropes is spun by the O. punicae female and is associated with stalked eggs; it appeared as a unique character in the CW-life type. Oligonychus afrasiaticus, also showed a new life type, 'CW-d,' when reared on the abaxial side of leaves of four host plants, viz., desert fan palm, maize, sorghum, and sugarcane. Oligonychus afrasiaticus showed a site for quiescence and a site for oviposition as variables, whereas the site for defecation (SD) was a persistent characteristic on all four tested host plants. Oligonychus pratensis showed the characteristics of the sub-type 'CW-u' on the abaxial leaf side of Washingtonia filifera (Lindl.) H. Wendl. (Arecaceae). The SD was a distinguishing behavioral characteristic used to separate O. afrasiaticus from O. pratensis when inhabiting the same host plant, W. filifera.

Field application of six commercial essential oils against Date Palm mite, Phyllotetranychus aegypticus (Acari: Tenuipalpidae) in Egypt

Field application of six commercial essential oils against Date Palm mite, Phyllotetranychus aegypticus (Acari: Tenuipalpidae) in Egypt

Field Population Sex Ratio of the Date Palm Mite, Oligonychus afrasiaticus (McGregor)

The effect of some abiotic and biotic factors on the population sex ratio of the date palm mite (DPM), Oligonychus afrasiaticus, were evaluated on four date palm cultivars in two regions (Riyadh and Qateef) of Saudi Arabia. The week of infestation, fruit stage, and their interactions, as well as the cultivar, significantly affected the DPM sex ratio. The DPM infestation, in the first week, started with a high female proportion (from 0.78 to 1) in both regions of the ‘kimri' fruit stage, and remained female-biased till the fifth week of infestation (from 1.5:1 to 4:1) with a growing DPM population density in both regions. The DPM sex ratio declined to equality (1:1) during the sixth week of infestation, the onset of the ‘khilal’ fruit stage, and further declined to a male-biased sex ratio (4:1) on the Selj, Hamra and Shaishie cultivars, with a declining DPM population density in the last week of infestation. The date fruit stage affected the sex ratio of DPMs negatively in Riyadh and positively in Qateef. The interaction between the week and fruit stage had a significant positive effect on the DPM sex ratio in Riyadh, and a negative effect in Qateef. This study of the DPM sex ratio could be a step in establishing a female-based sampling programme during the early weeks of infestation.

First record of Raoiella indica Hirst (Acari: Tenuipalpidae) in Jordan

ABSTRACTRaoiella indica Hirst (Prostigmata: Tenuipalpidae) is a mite with many hosts and has been reported in many countries. In the Middle East, this mite was reported on date palm in Egypt and Palestine. In 2017, a red mite was found on leaves collected from the date palm (Phoenix dactylifera) cultivars “Naboot Saif” and “Fahl Madsarti” growing at the University of Jordan Station, Jordan Valley. Mite specimens were collected and microscopically examined. Cytochrome oxidase I was sequenced to confirm identity and compare to other accessioned Raoiella sequences. Based on morphological and molecular characterization, identity was confirmed to be R. indica. The molecular characterization of the mite showed 99% similarity to accessions that originated from United Arab Emirates and Iran. To our knowledge, this is the first record of red date palm mite in Jordan on date palm trees.http://www.zoobank.org/urn:lsid:zoobank.org:pub:A44D3E74-A69C-488C-8638-1B7EB1177146

Webbing life type and behavioral response of the date palm mite, Oligonychus afrasiaticus, to webbing residues on leaves and fruits of date palm.

The present study examined the webbing life type and behavioral response of date palm mite (DPM) Oligonychus afrasiaticus (McGregor) toward its webbing residues, in presence or absence of immature individuals, on leaves and fruits of date palm. DPM exhibited a complicated web life type on both the leaves and fruits of date palm, which is characterized by the following features: complicated irregular web structure; webbing density on the leaves is medium and on the fruits extremely high; eggs are always laid on the threads of web without web cover; fecal pellets are deposited on the substrate surface (both leaf and fruit); quiescent stages are on the silken web threads; and the preferred site for feeding and walking is under the web. Behavioral observation of DPM females revealed that the midrib of leaves and the base of fruits of date palm were the preferred sites for feeding and web construction. The number and development stage of DPM affected the behavioral response of females on date palm leaves but not on the fruits. DPM spent most time feeding under the web on both the leaves and fruits of date palm.

Field studies on occurrence, alternate hosts and mortality factors of Date Palm Mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae)

The occurrence of date palm mite (DPM), Oligonychus afrasiaticus, its association with other mite species and alternate host plants were studied in nine provinces of Saudi Arabia during eight consecutive years (2011–2018). In addition, different mortality factors of DPM during the fruiting season were assessed in Riyadh city. The results showed that all DPM developmental stages were recorded on date palm young-aged fronds as well as grasses growing underneath the trees during off-fruit periods, even in severe winters. Interestingly, DPM was found only on narrow leaf alternate host plant species belonging to the families Arecaceae and Poaceae. Moreover, Hyphaene thebaica, Phoenix canariensis, Cenchrus ciliaris, Dichanthium annulatum, Hilaria sp., Hyparrhenia hirta, Pennisetum ciliarae, P. divisum, Pennisetum sp. and Aeluropus littoralis were reported for the first time as alternate host plants of the DPM. Two phytophagous mites, Eutetranychus orientalis and E. palmatus (Tetranychidae), and the predatory mite Spinibdella cronini (Bdellidae) were found associated with DPM on date fruits. However, the phytoseiid mite Cydnoseius negevi was found on the grasses growing under the trees. Amongst mortality factors, pathogens followed by predators were responsible of deaths in different DPM stages. However, the unknown environmental factors caused maximum mortality of all DPM stages than any other factor. Based on the obtained data, it is suggested that young-aged fronds should be sampled prior to fruit setting for early detection of DPM and consequently should be chemically treated during the off-season. In addition, the alternate host plants as well as date palm trees growing along the roadside should be chemically treated as they may be a source of DPM. Also, more attention should be given to search and conserve indigenous predators which can be used efficiently against DPM. It is anticipated that such data can provide valuable information to improve IPM program for controlling DPM in other regions of Saudi Arabia.

Response of the predatory mite Cydnoseius negevi (Acari: Phytoseiidae) to webbing of the date palm mite, Oligonychus afrasiaticus (Acari: Tetranychidae), on date palm fruits and leaves.

The behavioral response of a generalist phytoseiid predator, Cydnoseius negevi (Swirskii & Amitai) (Acari: Phytoseiidae) to the complicated webbing of the date palm mite (DPM) Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) was evaluated for the first time on date palm leaves and fruits, both in the laboratory and on field-collected samples. Cydnoseius negevi used its first pair of legs in a swimming-like to-and-fro movement to penetrate the complicated webbing of DPM and demonstrated three attack behaviors, i.e., patrolling (PG), web invasion (WI), and web penetration (WP), against the webbing of DPM on date fruits and leaves. The time spent by the predatoron attack behaviors was significantly longer in the laboratory for treatments where either more preyfemales or immature stages along with females were present. The time spent by C. negevi on response behaviors such as searching, grooming, and resting increased with increased number of DPM females and with the addition of immature stages along with DPM females. Cydnoseius negevi, even though being a generalist phytoseiid predator, showed its potential towards penetrating the complex dense webs of DPM on date palm fruits and leaves. If released in suitable numbers prior to establishment of DPM colonies, C. negevi may prove to be an effective biological control agent.

Field Evaluation of Date Palm Dust Mite, Oligonychus afrasiaticus (McGregor) Control on Date Palm Trees in New Valley Governorate of Egypt

The old world date mite (dust mite) Oligonychus afrasiaticus (McGregor) is one of the major pests of date fruit in the New Valley Governorate of Egypt. This pest mite affects the fruits of palm trees during the growth and ripening stages as they sucking the fruit juice, leading to stop fruit growth and destroying the crop. This research was carried out in Sharq El-Owainat province for evaluating the effects of biochemical acaricide (Vertimec 1.8% EC as 40 ml/100 liter of water), four acaricides (i.e. Abroch 5% SC as 50 ml/100 L of water, Challenger Super 24% SC as 60 ml/100 L of water, Envidor 24% SC as 30 ml /100 L of water and Ortus Super 5% EC as 50 ml/100 L of water), one insecticide (Tafaban 48% EC as 300 ml/ 100 L of water), a mineral oil (KZ oil 95% EC as 1L/100 L of water), sulfur (Micronite 80% WP as 500 g/100 L of water) and water for O. afrasiaticus in two date palm cultivars Barhi and Bartmoda. Results indicated that in date palm cultivar Barhi, Challenger Super and Vertimec were the most effective ones in reducing date palm mite population reaching 91.93% and 91.60%, respectively, followed by Abroch, Ortus Super, Tafaban and Envidor which gave reduction ranged between 85.07% to 87.74%. Micronite, KZ oil and water gave reduction between 71.77 and 82.82% after two weeks of application. Challenger Super, Vertimec, Ortus Super and Envidor were the most effective ones in reducing O. afrasiaticus population reaching 95.37%, 94.18%, 91.05% and 90.34%, respectively in date palm cultivar Bartmoda. Abroch, KZ oil, Tafaban, and Micronite was gave reductions between 77.79% and 82.74%. The lowest was water (61.93%) after two weeks of application.We suggest that use Challenger Super, Vertimec, Ortus Super and Envidor were the most effective ones in reducing O. afrasiaticus populations.

Effects of host plants on distribution, abundance, developmental time and life table parameters of Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae)

The biology and ecology of the date palm mite O. afrasiaticus have been studied through regular inspection in Tunisian oases and laboratory observations. Results indicate that the start date of fruit infestation varied between years and by date palm variety. Start dates ranged from the first week to the third week of July. The period spent by the mite on fruits varied from one variety to another; lasting 8 weeks on the Deglet Noor variety, 2 to 5 weeks on Alig, 2 to 4 weeks on Kentichi dates, and 2 to 4 weeks on Bessr fruits. The Deglet Noor variety was the most susceptible to O. afrasiaticus. Mite populations on the pinnae remained low from May through December. During autumn and spring, O. afrasiaticus was found on sorghum leaves in the orchard ground-cover. A life table study in the laboratory at 27°C on six host plants (fruits of date palms varieties Deglet Noor, Alig, Kentichi, Bessr, and Deglet Noor pinnae and sorghum leaves) showed that the life cycle of O. afrasiaticus differed among host plants with average values ranging between 13 on Alig fruits and 10.9 days on sorghum leaves. Relatively high fecundity was found on sorghum leaves (2 eggs/female/day) during 5.2 oviposition days, while low fecundity values occurred on Deglet Noor pinnae and Alig fruits with 0.7 eggs/female/day during 5.4 days. Average longevity of O. afrasiaticus females ranged from 13.4 to 7.5 days on Deglet Noor fruits and sorghum leaves, respectively. Intrinsic rate of increase (r m) was highest on sorghum leaves (0.171) and Deglet Noor fruits (0.166), and lowest on Alig fruits (0.103). Greater knowledge of life history traits and seasonal abundance of this species is needed in order to design appropriate control strategies.

Comparative Demography of the Spider Mite,Oligonychus afrasiaticus,on four Date Palm Varieties in Southwestern Tunisia

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of palm date fruits. Life cycle, fecundity, and longevity of this mite were studied on fruits of four date palms, Phoenix dactylifera L. (Arecales: Arecaceae)(varieties: Deglet Noor, Alig, Kentichi, and Besser), under laboratory conditions at 27 = 1 °C, 60 ± 10% RH. Total development time of immature female was shorter on Deglet Noor fruits than on the other cultivars. O. afrasiaticus on Deglet Noor had the highest total fecundity per female, while low fecundity values occurred on Besser. The comparison of intrinsic rates of natural increase (rm), net reproductive rates (Ro), and the survival rates of immature stage of O. afrasiaticus on the host plants suggests that O. afrasiaticus performs better on Deglet Noor fruits. The mite feeding on Alig showed the lowest intrinsic rate of natural population increase (rm = 0.103 day 1). The estimation of difference in susceptibility of cultivars to O. afrasiaticus is crucial for developing efficient pest control programs. Indeed, less susceptible cultivars can either be left unsprayed or sprayed at low threshold.