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Both prey type and abiotic conditions limit performance of phytoseiid predators. The exotic predatory mite, Typhlodromalus aripo developed and reproduced when maintained on eggs and active stages of the cassava green mite (CGM) Mononychellus progresivus at three different temperatures. At the highest temperature of 33 °C and the lowest at 12 °C, mite survival was less than 15 % over a period of ten days with low fecundity. At 12 °C, immatures took longer to reach maturity, while at 33 °C high mortality (>80 %) occurred. The best performance was recorded at 27 °C and 75 % relative humidity. Typhlodromalus aripo was also able to feed, develop and reproduce on the crawlers’ stage of the whitefly, Bemisia tabaci and the nymphal stage of the mealybug, Phenacoccus manihoti, though a low survival rate (

During a field survey of predatory mites in the different geographical zones of Lesotho, 13 species, including a new species, were recorded. Among them, Amblyseius addoensis (Van der Merwe and Ryke) was found common in the lowlands and Senqu valley. Amblyseius sehlabatei n. sp. was common in foothills and mountains. Observations showed that there is an altitude-floral species link. Further ecological studies are required to confirm such a hypothesis.

The predacious mite, Amblyseius cydnodactylon Shehata & Zaher (Phytoseiidae) is a common natural enemy inhabiting low growing plants like cucumber in Egypt. It has been recorded associated with infestations of the two-spotted spider mite, Tetranychus urticae Koch (Tetranychidae) and the white fly, Bemesia tabaci (Genn.) (Homoptera). Under laboratory conditions of 28–30°C and 70–80% R.H., the predacious adult female consumed nymphs of T. urticae at different experimental densities. However, the consumption rate increased with increasing prey densities up to 32 nymphs/female/day and decreased significantly at 64 and 128 nymphs/female/day. Addition of fixed numbers of 2nd instar nymphs of B. tabaci (10 individuals) to each TSSM prey density tested significantly reduced consumption of spider mites although the predator female responded in similar fashion to increasing prey densities. Reproduction increased with increasing prey densities and reached a maximum at 32 nymphs/female/day. The addition of n...

In a greenhouse study, the predatory mite Phytoseius plumifer (C. and F.) was released successively at two rates of 1 or 3 individuals per leaf on two groups of fig seedlings naturally infested with Tetranychus arabicus Attiah. A third group of plants was treated with dicofol 10 weeks after the predator release. T. arabicus population was suppressed and maintained at low densities when P. plumifer was reintroduced 10 weeks after the first release. Application of dicofol, however, killed the predator and thus allowing the prey population to rise again. Zusammenfassung Verwendung der Raubmilbe Phytoseius plumifer zur biologischen Bekampfung der Spinnmilbe Tetranychus arabicus (Acarina) an Feigensamlingen Bei einer Versuchsreihe im Gewachshaus wurde die rauberische Milbe Ph. plumifer in Mengen von ein oder drei Individuen/Blatt auf 2 Gruppen von Feigen-Samlingen ausgesetzt, die einen naturlichen Befall mit der Spinnmilbe T. arabicus aufwiesen. Eine 3. Samlingsgruppe wurde 10 Wochen nach Freisetzung der Pradatoren mit dem Akaricid Dicofol behandelt. Die Spinnmilben-Population wurde herabgedruckt und auf niedriger Dichte gehalten, wenn man die Raubmilbe 10 Wochen nach der ersten Freilassung erneut aussetzte. Durch Anwendung von Dicofol dagegen wurden die Rauber vernichtet und der Spinnmilben-Population Gelegenheit gegeben, sich wieder zu vermehren.

During a survey (March–June, 1995) of predacious mites on citrus in 30 major production areas, 25 species of phytoseiid and Anystid mites were recorded.Amblyseius pafuriensis Van der Merwe occurred almost at every sites in the Northern Transvaal and Southern Zimbabwe,A. citri (Van cer Merwe & Ryke) was most common in Central and Eastern Transvaal,A. citri andTyphlodromus crassus Van der Merwe, Natal, andA. addoensis addoensis (Van der Merwe & Ryke) andA. addoensis rubicolus (Van der Merwe & Ryke) in both Cape provinces. Regarding the whole region,A. addoensis addoensis, A. citri, A. addoensis rubicolus represented 86% of the total number of sampled predators,A. pafuriensis, T. crassus andT. rasilis Van der Merwe together represented 5% and the remaining 20 species represented 9%. The study indicated thatA. pafuriensis, T. crassus andT. rasilis can be excellent biocontrol agents on citrus.

Cassava green mite (CGM) of the Mononychellus genus is an invasive species in Africa, introduced from South America. Its phylogenetic diversity over geographical localities has never been assessed in East Africa, where mite density dynamics oscillate from few individuals to a peak of hundreds. The objective of this study was to determine CGM species comparative phylogenetic diversity from seven distinct geographical sites in East Africa. Six sites were sampled for CGM races, two samples from each country. DNA was extracted on internal transcribed spacer 2 (ITS2) and cytochrome oxidase subunit I (COI), and compared for phylogenetic variations of CGM from different locations of East African region. A comparative search from the NCBI Gene bank resulted into identical species nucleotides from Congo and Benin. Sequences from the two sites in Kenya were 99-100% similar to CGM nucleotide from the Congo-Benin accessions (X79902.1) on ITS2 gene region. On COI, a 98- 99% site sequences similarity was observed on M. progresivus accession X79901.1. A closely related divergence of specimens collected from Tanzania and Uganda was determined. Both Uganda and Tanzania had 99% match to X79901.1 on COI region. Similarly, the Uganda and Tanzania samples had 99% match to emb/X79902.1 on the 18Sr RNA region. The CGM sequence from coastal Kenya had the highest phylogenetic divergence from the Congo-Benin sequences. A small biogeographic phylogenetic divergence (0-1%) was evident from the analyses among the six collection sites. The results confirm M. progresivus identity in East Africa it also indicates intraspecies phylogenetic variations on the COI gene region of interest. Key Words : Benin, Congo, Kenya, Mononychellus progresivus

The cassava green mite (CGM), Mononychellus progresivus Doresta allowed for a limited development of the predatory mite, Phytoseiulus longipes Evans at three experimented temperatures. When the predators were confined with the motile stages of CGM, at 10 o C, only 10% of the larvae reached maturity after 16 days. At 24 and 32 o C the development on the same prey was improved, however less than 50% that reached maturity, were not able to produce eggs. At the same temperatures, on the tomato spider mite (TSM), Tetranychus evansi Baker & Pritchard, the developmental periods of P. longipes were shorter and mortality lower. P. longipes consumed less number of CGM when compared to TSM and about double the number of TSM prey when compared to CGM. Feeding only on CGM produced insignificant number of eggs with high rate of female mortality. Combination of both CGM and TSM at different ratios substantially improved reproduction and lowered mortality of P. longipes females.

The effect of manipulating cereal aphid population development, by either adding aphids or spraying with an aphid-specific insecticide, on the predatory mite fauna was investigated. Populations of the anystid mite, Anystis baccarum (L.) were very small until late June when numbers built up rapidly at the time of the aphid population decline. There was however, no significant relationship between aphids and numbers of mites over the whole season. Preliminary electrophoretic analysis of two enzymes in the gut of anystid mites indicated that they may have been feeding on thrips, Limothrips cerealium Haliday. The free-living soil Mesostigmata had two population peaks, each related, the first positively and the second negatively to aphid populations.

This study demonstrates a laboratory induction of a malathion - resistant strain in Amblyseius cydnodactylon Shehata & Zaher and effect of selection on reproduction. Initially 500 sensitive females obtained from a laboratory mass culture were exposed to malathion at LC70. Subsequent selections were conducted every two generations at progressive LC70 values and number of eggs/female/day was recorded at each selection. Experiments were carried out under laboratory conditions of 24-28°C and 70-80 % R. H. The LC70 in the parent generation was 5.19 ppm and increased to 20 ppm in F4 selection generation. The dosage mortality relationships continued to increase up to a maximum of 282.3 ppm in F16. The rate of developing resistance increased from 1.75 folds in F2 to 1.97 folds in F4 and gradually reached a maximum of 54.39 folds in F16. There was an obvious decrease in reproduction corresponded to increasing resistance. For example, the number of eggs/female/day in F 16 was 8 eggs, contrasting 3 eggs in the parent generation.

The predacious miteTyphlodromus pelargonicus El-Badry preyed on the different developmental stages of the two spotted spider miteTetranychus urticae Koch. The development was quickest and the number of prey consumed was highest when individuals were maintained on eggs compared with nymphs or adult female stages. The predator was able to develop and reproduce on the eriophyid miteEriophyes dioscoridis. Soliman & Abou-Awad, nymphs of the tobacco whiteflyBemisia tabaci (Genn.) and pollen grains ofPhoenix dactylifera andRicinus communis. The average number of eggs/♀/day was 1.4, 0.7, 1.2 and 0.9 on eriophyid, whitefly,Ph. dactylifera andR. communis respectively.

Effect of the nematicide carbofuran on the population development of the citrus parasitic nematodeTylenchulus semipenetrans and predacious soil mites in citrus orchard under organic manure regime of fertilization. In an Egyptian citrus orchard under farmyard manure regime of fertilization an experiment was conducted for three successive seasons (1993–1995) to investigate the potency of the nematicide carbofuran against the population of the citrus parasitic nematodeTylenchulus semipenetrans Cobb. and any side-effects on predacious soil mites. An initial reduction inT. semipenetrans populations was observed after application, although a remarkable increase in the population occurred afterwards. In contrast, the average number of predators decreased, particularly in 1995. In organic plots without nematicide, predators increased to great numbers andT. semipenetrans caused negligible injury. In the fertilizer-free treatment, theT. semipenetrans population was low although that of predacious mites was high. The study indicated that carbofuran treatments reduced the population of predacious soil mites and in their absence the population of the parasitic nematode,T. semipenetrans was likely to increase.

The cassava green mite (CGM), Mononychellus progresivus Doreste, causes serious leaf damage on cassava leading to low root yield in the dry savanna regions of Africa. A study to compare effectiveness of the predatory phytoseiid Typhlodromalus aripo (De Leon), an acaricide abamectin, an insecticide chlorpyrifos and fertilizer in management of CGM was carried out in various agro-ecological zones of the eastern dry low-midlands at Katumani (LM4), Kiboko (LM5), the cool upper midlands at Embu (UM2) and the warm humid coastal lowlands at Mtwapa (CL3) of Kenya. The acaricide abamectin was found most efficacious in controlling CGM at all agro-ecological zones. Further, the results revealed that the exotic phytoseiid T. aripo was effective in suppressing population densities of CGM by 45% in the dry-hot midlands (Kiboko) and 64% in the warm-humid coastal climatic zone, but the predator could not persist in the cool midlands. However, in the same cool midlands, high amounts of rainfall led to low CGM density of less than 20 mites per leaf, amid the presence of the indigenous phytoseiid Euseius fustis (Pritchard & Baker). Increase in CGM density was positively correlated to the warm and hot dry environment at the plots at Kiboko and Katumani. In the irrigated and wetter sites T. aripo increased with the increase in relative humidity in the environment at Kiboko and Mtwapa. Abamectin spray was the best option in suppressing CGM densities in the dry lowland zones. Similarly, soil fertility input led to higher yield in the sandy soils of low coastal and eastern midlands. High CGM densities did not result in low yield as other environmental factors such as soil fertility, and temperature influenced the final root yield. These findings give insight on the management options of the CGM pest in the different agro-ecological zones in Kenya and similar regions of Africa.

Flufenoxuron displayed various effects on the two spotted spider miteTetranychus urticae Koch according to the age and the concentrations tested. Generally, younger immatures were rather susceptible than the older ones. The duration of the developmental period increased due to treatments and reproduction of the succeeding females, at the different concentrations. The number of eggs/♀/10 days was fewer than in the control. Treated females at concentrations ranged between 400–20 ppm, produced none-viable eggs and viability increased by decreasing the concentration down to 1 ppm.

Four species in the genus Amblyseius Berlese are reported from Tanzania, A. serengati sp.n., A. fustis Pritchard and Baker, A. largoensis (Muma) and A. sawaga Pritchard & Baker. Descriptions and comparisons with similar species are provided for the new species.

(Erratum)

We surveyed the phytoseiid mites in four different geographical zones of Kenya: Zone I, upper highland and tropical alpine (2400–4400m); Zone II, lower highland (1800–2400 m); Zone III, midland (800–1800 m); Zone IV, tropical, hot and humid (0–800 m). A total of 107 species was found. In the subfamily Amblyseiinae there were 14 species in the genus Neoseiulus Hughes, one in Asperoseius Chant, one in Paraphytoseius Swirski & Schechter, five in Typhlodromips De Leon, five in Transeius Chant & McMurtry, one in Graminaseius Chant & McMurtry, 11 in Amblyseius Berlese, one in Arrenoseius Wainstein, two in Typhlodromalus Muma, seven in Ueckermannseius Chant & McMurtry, one in Amblydromalus Chant & McMurtry, 20 in Euseius Wainstein, one in Iphiseius Berlese, one in Phytoseiulus Evans and one in Gynaeseius Ehara & Imano. In the subfamily Phytoseiinae Berlese, there were four species in the genus Phytoseius Ribaga. In the subfamily Typhlodrominae Wainstein, there were four species in the genus Kuzinellus Wainstein, and 27 in Typhlodromus Scheuten.

The number of phytoseiid mite species varied greatly according to the geographical zones in Keyna. In the upper highlands (2400–4400m) 22 species were recorded, 44 in the lower highlands (1800–2400m), 57 in the midlands (800–1800m) and 25 in the lowlands (0–800m). The predacious mites Euseius kenyae (Swirski & Ragusa) and E. albizzae (Swirski & Ragusa) were common in Zones I, II and III and not reported in Zone IV. In contrast, E. minutisetus Moraes & McMurtry was common in zone IV and not recorded in the other three zones. The maximum number of Neoseiulus species were collected from upper highlands (Zone I), indicating some adaptation to adverse conditions. Similar adaptation were reported for largoensis species group as they were common in the mangrove localities (Zone IV) and rare in others. Some species had no distinct patterns of distribution and were almost sampled form every zone (e.g. Transeius Chant & McMurtry, Typhlodromus Scheuten and Typhlodromips De Leon).

Resistance has developed in the tomato russet mite,Aculops lycopersici (Massee) to the organophosphate, methamidophos. Laboratory studies showed thatA. lycopersici which received methamidophos for 3 years was highly tolerant. In contrast, it was very susceptible to dicofol and pyridaphenthion, and susceptible to cypermethrin. Pyridaphenthion and dicofol had long residual activity whereas methamidophos and cypermethrin had shorter activity.

Different ages of the two spotted spider mite Tetranychus urticae Koch and the predacious mite Amblyseius gossipi El-Badry eggs were exposed to selected concentrations of Cypermethrin (500 ppm), flucythrinate (200 ppm), cyfluthrin (100 ppm), fenvalerate (200 ppm), Pyridaphenthion (25 ppm), dicofol (250 ppm), avermectin (10 ppm), and dimilin (50 ppm). Generally, the synthetic pyrethroids were effective on eggs especially those of A. gossipi. Dicofol was rather toxic to T. urticae eggs, while avermectin was only effective on older eggs of both species. Eggs treated with different pesticides at late stages took longer to hatch, particularly in the case of A. gossipi.

When females of the predacious mite Phytoseius finitimus Ribaga ingested dicofol and avermectin with the prey Eriophyes dioscoridis Soliman & Abou-Awad, the egg production sharply decreased after 120 h in the former, while continued at a lower rate in the later respectively. Dicofol was moderately toxic when ingested, although, avermectin caused mortality increased by increasing the time of exposure to treated prey. Few immatures reached maturity when fed on treated prey with dicofol, contrasting better development and less immature mortality on avermectin treated prey. Zusammenfassung Untersuchungen uber die Uberlebensrate, Reproduktion und Entwicklung der rauberischen Milbe, Phytoseius finitimus (Acari, Phytoseiidae) nach Futterung mit Dicofol- und Avermectin-behandelten Beutetieren Bei weiblichen Raubmilben von Phytoseius finitimus, die uber die Beutetiere (Eriophyes dioscoridis) Dicofol und Avermectin aufnahmen, konnte man beim ersten Praparat eine deutliche Abnahme der Eiproduktion ab 120stundiger Fraszeit feststellen. Beim zweiten Praparat blieb die Eiproduktion auch bei langerer Fraszeit erhalten, allerdings auf niedrigerem Niveau. Wahrend bei zunehmender Futterungszeit mit Avermectin-behandelten Beutetieren die Wirkung auf die Raubmilbe anstieg, zeigte Dicofol diesbezuglich unterschiedliche Wirkungen. Wenige Tiere erreichten das erwachsene Stadium, wenn sie wahrend ihrer Entwicklung mit Dicofol-behandelten Beutetieren gefuttert wurden, dagegen zeigte sich bei Avermectin eine vergleichsweise bessere Entwicklung und geringere Mortalitat wahrend der Entwicklung.

The effects of the eriophyid miteAceria ficusCotte, the tetranychid miteTetranychus arabicusAttiah and castor-oil pollen on the development and fecundity of the phytoseiid predatorPhytoseius plumifer (C. & F.) were studied. The feeding capacity of all developmental stages ofP. plumifer onA. ficus was also considered.

The gall mite Eriophyes dioscoridis Soliman & Abou-Awad was much more sensitive to avermectin than to fenvalerate. On the other hand, the predacious mite Phytoseius finitimus Ribaga was more tolerable to avermectin than to fenvalerate. Residues of avermectin showed a longer activity on E. dioscoridis and a shorter one on P. finitimus, whereas fenvalerate showed the opposite. Avermectin was able to penetrate through the roots and killed mites in galls on stem at concentrations as low as 0.063 ppm. None of the gall individuals suffered mortality with fenvalerate or control treatments.

Coumarin and gallic acid decreased survival and reproduction of the twospotted spider mite, Tetranychus urticae Koch. Contacting treated leaves with both compounds at 250 ppm caused mortality and low reproduction when the time of exposure increased gradually from 2 h to 144 h. Survival of the immatures decreased when contacted treated discs although development periods and reproduction were normal. Treatment of eggs caused low mortality although high concentrations shortened the hatch time.

The predacious miteAmblyseius brazilli El-Banhawy was exposed to the synthetic juvenile hormone methoprene to see the biological differences resulting from the application of the compound and its toxicity. Methoprene was applied as leaf residues or incorporated with the diet (pollen or prey). By contact methoprene was less toxic. Only at the highest concentration (1000p pm) the number of individuals reaching maturity, the percentage of survival and the number of eggs decreased while the duration of the developing individuals increased. The compound was more effective when injested. Feeding on pollen mixed with 100p pm methoprene block the development of all the individuals and a negligible number of eggs was laid. A diet containing 10p pm methoprene permitted a percentage of the individuals to reach maturity and oviposit. The survival and reproduction of the females fed on a diet containing 10p pm methoprene were also low. All the delivered eggs hatched under the different treatments, which indicates that methoprene did not interrupt the hatching process.

The development was faster and reproduction was higher whenAmblyseius olivi Nasr & Abou-Awad fed on the eriophyid miteEriophyes olivi Zaher & Abou-Awad. The duration increased and reproduction decreased on the tetranychid miteTetranychus (T.) uriticae Koch. The predator female consumed daily 120 and 8 individuals ofE. olivi andT. (T.) uriticae respectively. The daily reproduction was as low as 0.6–0.3 eggs/♂/day when females were maintained on royal jelly, molasses, honey or their combinations.

The predacious mites Amblyseius emanus n. sp. and A. Peruanas n. sp. are described. New collection records for A. californicus McGregor and Phytoseiulus persimilis Athias-Henriot are also presented.

The direct toxicity of 5 common acaricides toAmblyseius brazilli El-Banhawy was tested. Omethoate proved to be the most toxic and Chlorobenzilate the least toxic. LC50 were 1.2ppm, 220ppm, 720ppm and 1250ppm for Omethoate, Mexacarbate, Dicofol, Mitran and Chlorobenzilate respectively. The indirect toxicity was also studied by providing the female predators with the phytophagous miteAponicus spinosus (Banks) previously treated by Chlorobenzilate and Mexacarbate. The females were fed on the treated as well as the untreated prey. The eg laying was interrupted and almost stopped in the case of Mexacarbate.

The predatory mites,Amblyseius gossypiElbadry andPhytoseius plumifer (Canestrini & Fanzago) successfully went through three generations on a diet of castor-oil pollen and were able to return to their natural prey,Tetranychus arabicusAttiah, apparently unaffected in a way except for a reduction in the predatory efficiency of adultA. gossypi.

Interaction of soil predacious mites and citrus nematodes (parasitic and saprophytic), in citrus orchard under different regime of fertilizers; Effect on the population densities and citrus yield.