Department of Plant Protection, Ankara University, Ankara, Turkey
Received date: 03/07/2017 Accepted date: 17/08/2017 Published date: 19/08/2017
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Determination of plant parasitic and beneficial mite diversity and population fluctuation of Tetranychus urticae Koch (Acari: Tetranychidae) were carried out on Strawberry (Rosaceae: Fragaria) fields between 2011 and 2013 in the Mersin province of Turkey. In outdoor strawberry fields, the mite composition has not been investigated comprehensively in this area. Fourteen plant parasitic, predatory and saprophagous mite species were established on strawberry leaves belongs to 5 families: Tetranychus urticae Koch (Acari: Tetranychidae) was the predominant harmful mite species all the sampled regions of Mersin while Neoseiulus californicus (McGregor), and Phytoseiulus persimilis (Athias-Henriot) were found common predatory species. Amblyseius swirskii (Athias-Henriot), Amblyseius andersoni (Chant), Euseius stipulatus (Athias-Henroit), Euseius finlandicus (Oudemans), Typhlodromus intercalaris (Livshitz-Kuznetsov) and Phytoseius finitimus (Ribaga sensu Denmark) which belong to the Phytoseiidae family and are identified beneficial mite species. Besides this, Proctolaelaps sp. (Ascidae) (Acari: Mesostigmata) was predatory mite, while Tyrophagus putrescentiae (Shrank) (Acaridae) (Acari: Astigmata) was identified as a saprophagous species. In terms of beneficial species, Phytoseiidae is the most common family. Tetranychus urticae Koch (Acari: Tetranychidae) have been found to be the most harmful and abundant pests species on strawberry plants causing severe damage. The aim of this study was to determination of plant parastic and beneficial mite species and observation of the population density fluctuations of Tetranychus urticae in three different regions of Silifke (Atayurt, IÅÄ±klÄ± and KurtuluÅ villages) in Mersin. The population density of T. urticae on strawberry plants began to increase in April and late-May and peaked three times in mid-April, late-May and mid-September. The data from the studies showed that biological control could be integrated to develop an effective mite management program.
Strawberry, Acari, Population, Neoseiulus californicus, Silifke
Approximately three million tons of strawberries (Rosaceae: Fragaria) are produced annually in different regions of the world . The strawberries produced in all South American countries amount to about 11,884 hectares and fruit production is 318,686 metric tons. Argentina and Brazil are the most important strawberry producers in South America .
Turkey is the 3rd biggest strawberry producer in the World with 376.070 tons of production from 13.234 ha in 2014 . Mersin, situated on the Southern Mediterranean Coast of Turkey, is the most important region with 45% of strawberry production and exportation. The strawberries are grown on a hill system in open fields under plastic tunnels. Cultivation of strawberries in plastic tunnels has increased considerably recently in Turkey . New strawberry cultivars, such as Chandler, Camarosa, and Sweet Charlie, contributed much to the level of production in this area [5,6].
Mites are very important pests both in greenhouses and outdoor cultivations including strawberry farms worldwide. They feed and lay eggs on the leaves and infested plants bear sterile blooms and become stunted or may even die [7,8].
The Two Spotted Spider Mite, feeds on strawberry (Fargaria spp.) leaves by piercing the mesophyll tissue [9,10]. A negative correlation between cumulative feeding mite-days and harvested yields was detected when plants became 80 mites per leaf . The Two Spotted Spider Mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an economically harmful pest due to its high rate of fecundity and short life cycle. This species can develop easily in different environmental conditions with low relative humidity and in optimum temperature 32°C . This species has 4-12 days from eggs to adult and may live for three weeks as an adult. Spider mites produce silk which protects the colonies from natural enemies and acaricides. The T. urticae individuals hibernate in the female stage in the litter and hidden places of the plants .
Due to broad morphological differences, Tetranychus urticae has been described with over 50 different synonyms and it is considered that it may be a species complex. T. cinnabarinus which has been reported in recent years as a morpho-type of T. urticae .
T. urticae and Tetranychus turkestani (Ugarov and Nikolski) (Acari: Tetranychidae) were the most important pest species on the strawberry in Turkey and in the world [8,13-16]. The Two Spotted Spider Mite (Tetranychus urticae), is the most common and severe plant parasitic mite that effects the production of strawberries [17-19].
Beside T. urticae, the phytophagous mite Phytonemus pallidus Banks (Acari: Tarsonemidae) is a very important pest of strawberry plantations in the United Kingdom. Among the predatory mites Neoseiulus californicus (McGregor) and N. cucumeris (Oudemans) (Acari: Phytoseiidae) were the most effective biological control agent .
Ten phytoseiid species were reported on strawberries in Latvia; Neoseiulus agrestis (Karg), N. aurescens (Athias-Henriot), N. barkeri (Hughes), N. bicaudus (Wainstein), N. cucumeris, N. herbarius (Wainstein), N. reductus (Wainstein), N. zwoelferi (Dosse), Typhlodromips rademacheri (Dosse) and Propriseiopsis okanagensis (Chant) .
The predatory mite Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae) was reported as a potential biological control agent of T. urticae on strawberry plants . It was mentioned that, Typhlodromus (Typhlodromus) pyri Scheuten, Typhlodromus (Anthoseius) rhenanus (Oudemans) (Acari: Phytoseiidae) and P. macropilis were the most abundant predatory mite species on strawberry plants in Norway and Brazil .
Many researchers have reported that the ecological balance was destroyed by large-scale use of acaricides and insecticides on mite and insect pests . Similarly, pesticides have been used so extensively by Turkish strawberry growers for a long time to control mite and thrips populations .
Biological control methods play an important role for the control of the population level of plant parasitic mites. The best known predatory mite species for biological control of spider mites on strawberry plantations commercially were P. persimilis, Galendromus occidentalis (Nesbitt); Neoseiulus californicus (McGregor) and Neoseiulus fallacis (Garman) (Acari: Phytoseiidae) [5,10,29].
In outdoor strawberry fields, the mite composition has not been investigated comprehensively in Mersin-Turkey. The aim of this study was to conduct a survey to determine plant parasitic and predatory mite species strawberry field plantations in Mersin. The identification of plant parasitic and beneficial mites and establishment of their occurrence rate during the growing season of strawberry fields is the objective of this study. Beside these the determination of population density fluctuations of T. urticae in three different areas of Silifke (Atayurt Town, Işıklı and Kurtuluş Villages) from January 2011 to June 2013 of Mersin was the objective of this study due to the establish of mite management programme which depends on protecting ecological balance.
The work was conducted strawberry plantations in southern Turkey (Mersin), from January 2011 to August 2013 (Figure 1). This is a humid area where the humidity level was higher between January to June and represented the Mediterranean climate condition. Geographical data and a map of the surveyed areas showing where various strawberry varieties are grown are provided in Table 1 and Figure 1.
|Mersin Silifke (Merkez)||36°.22',31.0836'' North 33°.55',59.4696'' East|
|Mersin Silifke (Atakent)||36°.24’1.5444” North 34°3’35.8668” East|
|Mersin Silifke (Atayurt)||36°.22',53.5512'' North 34°,1',45.5916'' East|
|Mersin Silifke (Taşucu)||36°.19',7.0139'' North 33°.52',53.7312'' East|
|Mersin Silifke (Yeşilovacık)||36°.11',40.902'' North 33°.39',59.4972'' East|
|Mersin Silifke (Akdere)||36°.14',25.0512'' North 33°.45',1.34639'' East|
|Mersin Silifke (Kabasakallı)||36°.23',38.8032'' North 33°.59',25.188'' East|
|Mersin Silifke (Arkum)||36°.21',6.7356'' North 34°.3',15.8328'' East|
|Mersin Yenişehir||36°.51',58.2624'' North 34°.29',10.8924'' East|
|Mersin Akdeniz||36°.48',15.1308'' North 34°.38',18.8484'' East|
|Mersin Mezitli||36°.48',15.1308'' North 34°.38',18.8484'' East|
|Mersin Toroslar||36°.48',15.1308'' North 34°.38',18.8484'' East|
|Mersin Anamur||36°.4',30.54'' North 32°,50',18.7404'' East|
Table 1: Sampling areas of Mersin, location and coordinates.
The geographical data related surveyed areas are showed on Table 1.
The study was carried out in a strawberry plantation of Mersin, for the determination of plant parasitic and predatory mite species in fields regardless of whether sprayed or not sprayed. Regular surveys were conducted Akdeniz, Mezitli, Toroslar, Yenişehir and Silifke region of Mersin during January to July of 2011 to 2013 (Figure 1).
During the surveys, the strawberry fields were applied by grower’s regular procedures involving application of fungicides, insecticides and acaricides.
Fifty fully-expanded trifoliate strawberry leaves were randomly sampled at monthly intervals from each field of the surveying areas at each sampling date. The leaves were taken in different levels and height of plants. The collected leaves were put into vinyl bags and then an ice-chilled cooler. The leaves were stored in a refrigerator until examined. Mites on the leaf samples were examined both with a stereoscopic microscope and by extracting with a Berlese funnel . The collected mites were preserved in alcohol (70%), then were cleaned, stained and mounted in Hoyer’s medium . The numbers of each mite species were counted in samples. Based on the slides for each species of abundance (the total number of mites). Species identification of mounted mites was carried out according to Jeppson et al. , Hughes , Papadoulis et al. , Faraji et al. , Seeman and Beard .
Population Densities of Mites in Strawberry Fields
Tetranychus urticae (Acari: Tetranychidae) was found to be the most harmful and common plant parasitic mite species on strawberry plants. Beside the species determination survey studies additional studies apart from that carried out at weekly interval for the determination of population fluctuations of T. urticae in three different areas of Mersin-Silifke (Atayurt Town, Işıklı and Kurtuluş Villages) from January 2011 to August 2013 of Mersin.
The leaves were taken for determination of population density fluctuations of T. urticae, from 1-5 da fields of Camarosa which is the main cultivated strawberry cultivar, at three different localities of unsprayed (since the estimation of the natural population fluctuation of Tetranychus urticae population) of strawberry fields in Silifke. For observing mite population, the presence of at least one mite active stage or egg considered. The leaf samples were collected at three different level of directions in each sampling site and density. From such samples data on population fluctuation of spider mites have been obtained. The average plant parasitic mite numbers (T. urticae) were estimated from the 50 leaves by “leaves/cm2”. The number of leaves with mites divided by the total number of leaves sampled. The average number of mites per infested leaf and calculated per unit area of cm2. These measures can be expressed per locations, dates and seasons/years.
Population density fluctuation of phytophagous mites was obtained from all surveyed areas between 2011 and 2013. Average diversity and abundance of plant parasitic and predator mites obtained from all survey areas in the same duration mentioned above, depends on number of individuals of a species as a percentage of total individuals (all species) in a sample, and domination is number of a species as a percentage of total individuals (all species) in all samples. The climate data’s were obtained from meteorological stations in Mersin during the sampling periods.
Mite Species on Strawberries in Mersin
Identified mites belonging to 14 species representing in 5 families were obtained from the strawberry growing areas in Mersin between 2011 and 2013. The proportional distribution of species is given in Table 2.
|Order||Family||Species||Feeding Habit*||Number of Specimen||Ratio|
|Prostigmata||Tetranychidae||Tetranychus urticae (Koch.)||Phy.||1244||91|
|Amblyseius swirskii Athias-Henriot||Pre.||3||0.22|
|Neoseiulus californicus (McGregor)||Pre.||32||2.36|
|Phytoseiulus persimilis Athias-Henrio)t||Pre.||21||1.55|
|Euseius finlandicus (Oudemans)||Pre.||2||0.14|
|Euseius stipulatus (Athias-Henriot)||Pre.||2||0.14|
|Phytoseius finitimus Ribaga||Pre.||5||0.35|
|Typhlodromus intercalaris (Livshitz – Kuznetsov)||Pre.||1||0.07|
|Astigmata||Acaridae||Tyrophagus putrescentiae (Schrank)||Gen.||1||0.07|
Table 2: Mite species and their proportional distribution on strawberry fields in Mersin provinces of Turkey in 2011-2013.
The most common distributed plant parasitic mite family belonged to Tetranychidae with 3 species, representing 93.2% of mites collected. In addition, the second most abundant families were predatory mites of Phytoseiidae (8 species). Beside this, Proctolaelaps sp. (Mesostigmata: scidae), and Tyrophagus putrescentiae (Shrank) (Acaridae) were identified. In our study, the phytophagous cosmopolite species Tetranychus urticae Koch (Tetranychidae) were abundant species in all locations. Other pest species were Bryobia rubrioculus (2.1%) and Eotetranychus (0.07%) which had very low density compared to T. urticae, the most common plant parasitic mite found.
N. californicus (McGregor) (Phytoseiidae) (50%) was the most common predatory mite species, among the beneficial mite species while P. persimlis (% 28) and Amblyseius andersoni (% 4) were second and third most common among the beneficial mites (Figure 2).
Considering predatory mite species, the highest ratio belongs to Phytoseiidae members, correlated with humidity and temperature conditions of the sampling area. Although the phytophagous mite diversities of the surveyed areas were found to be lower than those of predatory mites, their abundance ratio was higher than both those of predatory and saprophagous mites. Similar to our results, it has been reported that the abundance of plant parasitic mites exceeds predatory mites on a lot of plant species [36-39].
Population fluctuation and densities of phytophagous mite Tetranychus urticae on strawberry plants in Mersin.
The population fluctuation and densities of phytophagous mites on strawberry plantations in Mersin provinces (in three different localities; Atayurt Town, Işıklı and Kurtuluş Villages) were investigated during 2011 to 2013.
Işıklı Village, Tetranychus urticae density fluctuations during 2011 to 2013 (Figure 3). In 2011, an increasing of the average mite density was observed very early season due to the very hot weather conditions in January, 2011 in this village.
The mite density reached 0.8 individuals/cm2 in February and 3.5 to 4.26 individuals/cm2 during April and May. The highest value reached was 4.46 individuals/cm2 in June. T. urticae population density began to decrease until September and increased afterwards (Figure 3).
In 2012, the population density of mites was observed as 0.2-0.6 individuals/cm2 from January to April due to cold weather conditions. After this, phytophagous mite density continued at a very low level until May, because of the heavy rainy season. The density reached 4.5 individuals/cm2 at the middle of the May. The population decreased during June and July. It began to increase during August and reached its highest level in September and October and decreased afterwards (Figure 3).
In 2013, the population density of Tetranychus urticae were started to rise in January and February slightly earlier than the same time in the previous two years. In March, the population density changed by 1.8-3.2 individuals/cm2. The peak value was 4.8 mites/cm2 in May (07.05.2013). The temperature and humidity increased in June, when the population value began to fall (Figure 3).
Mersin-Işıklı had cooler weather conditions during November and December in 2011. The rainfall was observed to be intense and sometimes there was heavy rainfall, which affected the mite population density. The low temperature and higher precipitation caused a considerable decreasing of the mite population.
Atayurt Town; Tetranychus urticae density fluctuations during 2011 to 2013 (Figure 4). T. urticae population fluctuation studies started from January 2011 and continued until June of 2013 in Atayurt. The density of harmful mite population is higher in this region than the other regions. Only in periods of heavy precipitation, and particularly during heavy rainfall periods, the mite population fallen down (Figure 4).
In 2011, mite population density started to increase from January to May (1.4 mites/cm2), and reached its maximum level in early June 2011 (5.2 mites/cm2). Mite density was lower from June to September 2011 and began to increase afterwards. The following peak values which were observed at September (3.02 mites/cm2 (29.09.2011), due to higher average temperature and relative humidity. Mite population density level was lowest during December (Figure 4).
After February 2012, the population started to increase in Atayurt town. The population reached the highest value at 02 May, 2012 with a value of 4.8 mites/cm2, the population had started to fall by June 2012 (Figure 4).
Tetranychus urticae population decreased considerably due to the increase of temperatures (40°C) in July, started to increase end of August and then there was a temporary increasing in September and October. The density of mites decreased to 0.6/cm2 in November and December 2012.
In 2013, T. urticae population density was higher in January than previous years. The population density of T. urticae varied from 0.5 to 2.1 individuals/cm2 in January and February (Figure 4). It was observed that the density of mites were 5.2, 4.8 and 4.9 individuals/cm2 on 02.05.2013, 07.05.2013 and 12.05.2013 respectively (Figure 4).
Kurtuluş Village, Tetranychus urticae density fluctuations during 2011 to 2013 (Figure 5). Similar to the other two regions, the temperature of the Kurtuluş village was a little cooler in January and February. For this reason, the concentration of mite population was lower initially.
In March 2011, the density of mites began to increase, reaching its highest level in May (3.4 individuals/cm2) and in June 2011 (4.5 mites/cm2), after which the population remained low due to high temperature and high humidity until late August of the year. The population started to increase after September 2011, which was lower than in other regions. Since Kurtuluş is at a higher altitude, the falling of the mite population started earlier than in the other regions. The highest peak value observed was 1.037 individuals/cm2 (29.09. 2011) (Figure 5).
In January 2012, the mite population density was very low; 0.2, 0.7, 2.4, 2.6, and 3.2 individuals/cm2 in the period from January to May respectively. From the middle of May to June the mite population began to rise. The highest value reached was 4.7 individuals/cm2 in May. The population started to fall (4.2 mites/cm2) in June; afterwards the mite population fell considerably in July and a slight increase was observed in August. At the end of October, the population started to decline again. The mite number varied between 0.04 and 0.3 mites/ cm2 in November and December 2012 (Figure 5).
In 2013, Tetranychus urticae population density rose from 0.7 to 1.1 individuals/cm2 and then fell back to 0.7 individuals/ cm2 in January. The values were higher than the previous years and varied between 0.7-1.8 individuals/cm2 in January and February. Population density increased to 4.7 individuals/cm2 at the beginning of May, with high temperature and humidity during the spring months (Figure 6a-6c).
The population density of T. urticae in all three horticultural provinces in 2011, 2012 and 2013 increased from February to March, with the exception of regional differences. The population reached its highest level in April-May and the population decreased with increasing temperature and humidity after mid-June. These periods were also the main production periods for strawberry plants in this region. During the summer months, the population was low and increased again in the autumn months.
The population density varied with temperature, humidity, precipitation, the location of the fields, pruning strawberries, and weed clearance. Looking at the 2013 annual climate data, it was observed that the temperature was higher and this explains higher population density of Tetranychus urticae in January and February 2013 (Figure 6a-6c).
This is the first detailed studies concentrates on phytophagous and beneficial mites on strawberry fields in Silifke-Mersin of Turkey. The phytophagous and predatory mite fauna were relatively rich in Mersin. The phytoseiids were abundant in all growing seasons, which is mostly in tunnels and open fields in Mersin-Turkey.
We identified B. rubrioculus and Eotetranychus sp. as phytophagous in lower proportion. Beside this, eight phytoseiid and one Proctolaelapse species (A. andersoni; A. swirskii, N. californicus, P. persimilis, E. finlandicus; E. stipulatus; P. finitimus and T. intercalaris) beneficial mites, one saprophagous (Tyrophagus putrescentiae) and one Cryptostimgata sp. were identified on strawberries in Mersin. Tetranychus urticae is a major pest and Neoseiulus californicus is its most important and common established predatory mite in strawberry fields in this region while P. persimilis and A. andersoni followed this species.
The phytoseiid species Phytoseiulus persimilis (Athias-Henriot), Neoseiulus californicus (McGregor), (Oudemans) and Amblyseius swirskii Athias-Henriot, are used commercially in strawberry fields in Turkey and the world [8,29]. N. californicus was determined previously as an effective predatory mite for strawberry plants in Turkey . As an addition to our survey in Mersin, we identified Propriseiopsis okanagensis Chant (Acari: Phytoseiidae) and Tarsonemus pallidus Banks (Acari: Tarsonemidae) in the samples on strawberries from Adapazarı.
Tetranychus urticae populations were controlled by Neoseiulus fallacis (Garman) (Acari: Phytoseiidae), over 12 weeks in 2.5 ha following minimal inoculations into a strawberry field . The effect of different release rates of Neoseiulus californicus (McGregor), significantly reduced the phtophagous mite population on strawberry plants . N. californicus attacked most often Phytonemus pallidus (Banks) (Acari: Tarsonemidae) on strawberry plants and Amblyseius andersoni Chant (Acari: Phytoseiidae) fed on the cyclamen mite successfully (Croft et al.). In the greenhouse production of strawberries in Argentina, predatory and plant parasitic mite population fluctuations and spatial distribution followed each other . Ten Phytoseiidae species were reported on strawberries from Latvia. It was established that Phytoseiidae are important biological control agents of phytophagous arthropods, especially of mites [20,43].
T. urticae, T. cinnabarinus, Panonychus ulmi (Koch), Petrobia lupini (McGregor) (Prostigmata: Tetranychidae), Steneotarsonemus fragaria (Zimmerman), S. pallidus (Banks) (Prostigmata: Tarsonemidae), Phytoseiulus persimilis, Euseius finlandicus (Oudemans), Neoseiulus picketti (Specht) and Kampimodromus aberrans (Oudemans) (Mesostigmata: Phytoseiidae) were identified as common plant parasitic and predatory mite species on strawberries from Greece .
T. cinnabarinus andT. urticae were determined as the most abundant and common phytophagous species. These species were also observed on strawberry plants from different countries [13,15,44]. Neoseiulus californicus and N. cucumeris (Oudemans) (Acari: Phytoseiidae) were more effective predators than Typhlodromus pyri Scheuten (Acari: Phytoseiidae) on the phytophagous mites Tetranychus urticae and Phytonemus pallidus (Banks) (Arachnida: Acari: Tarsonemidae) on strawberries in England . The peak densities of T. urticae were lower than economic thresholds in open strawberry fields both in Norway and Brazil. The plant parasitic mite population has been restrained mainly by rainfall in the open field and by predatory mites in the tunnels .
Sabelis  revealed that moist and warm weather conditions are virtual requirements for the reproduction and development of mites. The mite populations reached their highest level during April and May in the strawberry fields in Aydın, which is similar to our results . Population Density fluctuation of Two Spotted Spider Mite (Tetranychus urticae Koch) reached economic threshold level two times in a year on strawberry in Mersin. The mite population density is accepted as 3-5 individuals as spray thresholds per leaf unit, it is necessary to take into account peak values as spraying times of strawberry. Seasonal accumulations of different levels of mite infestation levels on strawberry plants significantly reduced yield [46-48].
As a conclusion, it is very important to identify the plant parasitic and predatory mite species as species level and their population density for the assessment of effective control methods. We found that predatory mite fauna is rich and also occurred predatory mite species naturally. These results suggest that the phytoseiid species are a potential biological agent for the suppression of T. urticae populations in outdoor strawberry plantations in Mersin.
We found that Neoseiulus californicus (McGregor) is a better choice for the population development studies and biological control agent because they are the most common and abundant predatory mites in this region.
Funding for this study was provided through grants by the Turkish Council of Research (TUBITAK TOVAG Grant No: 112 O 042).