Do domatia mediate mutualistic interactions between coffee plants and predatory mites?

Ethanol producers eager for new technology to get more fuel from corn

Evaluation of entomopathogenic fungi for the control of Tetranychus urticae (Acari: Tetranychidae) and the effect of Metarhizium brunneum on the predatory mites (Acari: Phytoseiidae)

Plants may protect themselves against herbivorous arthropods by providing refuges to predatory arthropods, but they cannot prevent herbivores from taking countermeasures or even from reaping the benefits. To understand whether plants benefit from providing self‐made refuges (so‐called domatia), it is not only necessary to determine the fitness consequences for the plant, but also to assess (1) against which factors the refuge provides protection, (2) why predatory arthropods are more likely to monopolise the refuge, and (3) how herbivorous and predatory arthropods respond to and affect each other in and outside the refuge. In this article, we focus on the last aspect by studying the dynamics of refuge use of a predatory mite (Typhlodromalus aripo) and its consequences for a herbivorous mite (Mononychellus tanajoa) on cassava plants in Benin, West Africa. The refuge, located in‐between the leaf primordia of the cassava apex, is thought to provide protection against abiotic factors and/or intraguild predators. To test whether the predator waits for prey in the apex or comes out, we sampled predator‐prey distributions on leaves and in the apex at 4 hour‐intervals over a period of 24 hours. The predatory mites showed pronounced diurnal changes in within‐plant distribution. They were in the apices during the day, moved to the young leaves during night and returned to the apices the next morning. Nocturnal foraging bouts were more frequent when there were more herbivorous mites on the leaves near the apex. However, the foraging predators elicited an avoidance response by mobile stages of their prey, since these were more abundant on the first 20 leaves below the apex during late afternoon, than on the same leaves during night. These field observations on cassava plants show that (1) during daytime predatory mites monopolise the apical domatia, (2) they forage on young leaves during night and (3) elicit avoidance by within‐plant, vertical migration of mobile stages of the herbivorous mites. We hypothesize that cassava plants benefit from apical domatia by acquiring protection for their photosynthetically most active, young parts, because predatory mites (1) protect primordial leaves in the apex, (2) reduce the densities of herbivorous mites on young leaves, and (3) cause herbivorous mites to move down to less profitable older leaves.

We examined the influence of acarodomatia in the riverbank grape Vitis riparia Michaux (Vitaceae) on the distribution and abundance of predatory mites (Phytoseiidae) and their interactions with herbivorous mites. Acarodomatia are tufts of nonglandular trichomes or pits located in major leaf vein axes of many species of woody perennial plants and are often occupied by predatory and mycophagous mites. In common garden plantings of different accessions of V. riparia we found a significant positive relationship between size of domatia and the abundance of naturally occurring predatory mites. Behavior of adult predatory mites may explain this positive association, in part. In separate laboratory experiments, gravid females of Typhlodromus pyri Scheuten and Amblyseius andersoni Chant spent more time and deposited more eggs on half of a V. riparia leaf with accessible domatia versus the other half in which access to domatia was blocked with pruning tar. Domatia also had population consequences. In an outdoor experiment using potted grapevines, population size of T. pyri and A. andersoni mites was greater on V. riparia with open domatia compared to V. riparia in which domatia were blocked with pruning tar. Population size of predatory mites was also greater on V. riparia with domatia than on Vitis vinifera L., whether their axils were blocked or not. Since V. vinifera have very small domatia, these results indicate that the presence of domatia is important, not just access to vein axils. Elevated predatory mite populations in response to domatia, however, did not translate into differences in the abundance of European red mite Panonychus ulmi (Koch), an important pest of grapes.Overall, these results indicate that domatia in uncultivated V. riparia promote higher densities of some species of generalist phytoseiid mites. However, domatia are small in most cultivated grapes. We crossed females and males of V. riparia that varied in domatia size and reared their offspring and found that average domatia size in the parents was highly correlated (r2= 0.77, slope = 0.55) with average domatia size in offspring (high narrow‐sense heritability). Given that V. riparia possesses many other desirable agronomic traits, this result suggests it should be practical to breed for well‐developed domatia in cultivated accessions.

Interactions between microbial-feeding and predatory soil fauna trigger N2O emissions

This study investigated mite biodiversity and density on Capsicum annuum in temperate (Bursa and Yalova provinces) and semi-arid (Ankara province) zones of Turkey from 2009 to 2010. A total of twenty-six phytophagous, predatory and generalist mite species were established on pepper leaves. Tetranychus urticae (Tetranychidae) was the single predominant species on the plants in all zones, while Phytoseius plumifer, Neoseiulus californicus (Phytoseiidae) and Tarsonemus bifurcatus (Tarsonemidae) were found to be other common species. Mite diversity and density were higher in temperate zone provinces than in Ankara, which has semi-arid conditions. This variation was significantly correlated with high humidity in the temperate zone, but only for phytophagous mites. The highest number of predatory species was found in the temperate zone, a finding also correlated with humidity, but not significantly. Although phytophagous mite diversity was lower than that of predatory mites in both zones, phytophagous mites were more than abundant than both predatory and generalist mites. The current study observed a significantly high population density of T. urticae from late July to mid August of 2010 and 2011. The sharp decline in T. urticae density on pepper was found to be associated with the onset of rainfall in June and September. Consequently, similar population growth patterns in phytoseiids [Neoseiulus bicaudus, N. californicus and Typhlodromus (Anthoseius) recki in Bursa and Yalova; Phytoseius plumifer in Ankara] were found in all zones and in both years. Generally, predatory mite density showed a gradually increasing population growth pattern from late July to early October.

To analyze the differences of community structure of soil mites between the rocky desertification environment and karst beech forests, we investigated the soil mites of Quercus variabilis forest in the Chaoying small watershed of Guizhou Province. Soil mites from 83 genera, 54 families, and 3 orders were collected in the four investigations of 2014. We analyzed the differences of genus numbers, individual numbers, individual density, Shannon diversity index (H), Margalef richness index (SR), Pielou evenness index (J), maturity index (MI) of predatory soil mites (Mesostigmata: Gamasina), community structure of the oribatid mites (MGP) and nutritional structure of mite. Results showed that Oribatida was dominant in taxonomic richness and individual abundance. Abundant genus, high individual density and diversity of soil mites were found in summer and autumn, and higher individual abundance was found in spring and autumn. Soil mites showed surface-aggregation in their distribution. Most predatory mites were K-selected in summer and r-selected in other seasons. The ecological groups of the oribatid mites were mainly P-type and O-type. Hypochthonius, Allobelba and Zygoribatula constituted the nutrient function group of the soil mites. There were significant differences in the main groups of soil mites in the beech forest and other forest types. Among all the groups, Parholaspididae, Laelapidae, Oppiidae and Haplozetidae with abundant genera composition, Multioppia, Parholaspulus, Scheloribates and Haplozetes with predominance could be used as a biological indicator for the soil environment in beech forests.

The spider mite, Tetranychus urticae, is the major strawberry pest in Brazil. The main strategies for its control comprise synthetic acaricides and predatory mites. The recent register of a commercial formula of azadirachtin (Azamax(®) 12 g L(-1) ) can be viable for control of T. urticae. In this work, the effects of azadirachtin on T. urticae and its compatibility with predatory mites Neoseiulus californicus and Phytoseiulus macropilis in the strawberry crop were evaluated. Azadirachtin was efficient against T. urticae, with a mortality rate similar to that of abamectin. In addition, the azadirachtin showed lower biological persistence (7 days) than abamectin (21 days). Azadirachtin did not cause significant mortality of adult predatory mites (N. californicus and P. macropilis), but it did reduce fecundity by 50%. However, egg viability of the azadirachtin treatments was similar to that of the control (>80% viability). The use of azadirachtin and predatory mites is a valuable tool for controlling T. urticae in strawberry crop. Azadirachtin provided effective control of T. urticae and is compatible with the predatory mites N. californicus and P. macropilis. It is an excellent tool to be incorporated into integrated pest management for strawberry crop in Brazil.

1. Although theory suggests that intraguild predation destabilises food webs and may result in exclusion of species, empirical observations of food webs reveal that it is a common interaction. It has been proposed that habitat structure reduces the interaction strength of intraguild predation, thus facilitating the coexistence of species. 2. This was tested using acarodomatia, tiny structures on plant leaves, and predatory mites, which usually reside in these domatia. Sweet pepper plants ( Capsicum annuum L.) were used, which possess domatia consisting of tufts of hair, and coffee plants ( Coffea arabica L.) with pit‐shaped domatia. 3. On sweet pepper, the predatory mites Neoseiulus cucumeris Oudemans and Iphiseius degenerans Berl. feed on each other's juveniles. Larvae of each of the species were therefore used as intraguild prey with adult females of the other species as intraguild predators. On coffee, a similar set‐up was used, with larvae and adult females of Amblyseius herbicolus Chant and Iphiseiodes zuluagai Denmark & Muma as intraguild prey and intraguild predators, respectively. 4. Domatia on detached, isolated sweet pepper and coffee leaves were either closed with glue or left open, after which larvae and adult predators were released. As a control, larvae were released on leaves with open or closed domatia without an adult predator. 5. Survival of larvae was high in the absence of the adult (intraguild) predator. In the presence of the intraguild predator, survival was significantly higher on leaves with open domatia than on leaves with closed domatia. 6. This shows that even such tiny structures as plant domatia may significantly affect the interaction strength of intraguild predation.

A total of twenty three species of phytoseiid mites were recorded during the period of investigation those were belonging to the genera Amblyseius, Euseius, Paraphytoseius, Typhlodromips, Scapulaseius, Phytoseius, Neoseiulus, Anthoseius, Indoseiulus and Gynaeseius. Among the phytoseiid mite, Amblyseius largoensis was found as dominant predatory mite species occupied 20.55% of total predatory mite population followed by Euseius alstoniae and Euseius ovalis accounting for 9.27 and 7.64% of total predatory mite population, respectively. However, the other predatory mites belonging to the family viz., Tydeidae, Bdellidae, Ascidae, Cunaxidae, Cheyletidae and Stigmaeidae were also recorded in flower plants ecosystem. Regarding phytophagous mites, Tetranychus urticae, Schizotetranychus baltazari, Eutetranychus orientalis, Oligonychus indicus, Polyphagotarsonemus latus and Brevipalpus phoenicis were recorded as destructive mite pests.

Oligonychus ilicis (McGregor, 1917) (Acari: Phytoseiidae) is considered one of the main phytophagous mites of coffee plants (Coffea spp.). Although not considered as principal, it was already referred as the second in importance for the Conillon coffee plant, Coffea canephora Pierre & Froehn er. It is commonly in equilibrium, probably due to the presence of natural enemies, among them predatory mites belonging to the Phytoseiidae family. This work had as objectives to evaluate the O. ilicis population dynamics through the months of the year, the phytoseiids associated, and the spatial distribution of those mites in coffee plants. Studies were carried in a 1.3 ha coffee field located at EPAMIG, Lavras, Minas Gerais. Biweekly, ten leaves of superior, medium and inferior thirds (five leaves from each plant side) were randomly sampled from ten plants. The appraised leaves were removed from the third or fourth pair from the branch extremity. O. ilicis occurred along the whole period, being found in larger number of eggs than post-embryonic phases. Number of eggs in the medium and inferior parts of the plants was bigger than in the superior part. The periods of larger occurrence of O. ilicis coincided with the low pluvial precipitation time. Five species of predatory mites were found: Iphiseiodes zuluagai Denmark & Muma, 1972, Amblyseius herbicolus (Chant, 1959), Euseius citrifolius Denmark & Muma, 1970, Euseius concordis (Chant, 1959) and Euseius alatus DeLeon, 1966. The most abundant species was I. zuluagai, representing 72.4% of the phytoseiids collected and occurring during all the studied period.

Silicon (Si) may benefit the growth and physiology of various cultivated species, especially under stress conditions. Here, we hypothesized that soil Si supplying as Ca2SiO4 would increase the drought tolerance and water use efficiency of young Coffea arabica L. (Arabica coffee) plants, by maintaining shoot water status and photosynthesis under low water availability. To test such a hypothesis, morphological and physiological (leaf water potential, leaf gas exchange, photochemical activity, chlorophyll content) traits of coffee plants were evaluated under varying soil Ca2SiO4 applications (0, 3000, 6000 kg ha−1) and water availability. The chemical composition of plant tissues was evaluated under well-watered conditions after six months of Ca2SiO4 application, with fertilized plants showing higher concentrations of Ca (leaves and roots) and B (all plant organs) as compared to plants not supplied with Ca2SiO4 (control treatment). As there were no changes in Si concentration in plant organs under Ca2SiO4 application, our data indicate that the coffee species is a Si non-accumulator, or at least the cultivar ‘Catuaí Vermelho’ evaluated herein. Additionally, the photosynthetic capacity of coffee plants increased with 6000 kg Ca2SiO4 ha−1 compared to the control under well-watered conditions, as given by increases in gross and net photosynthesis under light saturation, light saturation point, maximum RuBisCO carboxylation rate, maximum electron transport-dependent RuBP regeneration, and maximum rate of triose phosphate use. Such photosynthetic improvements underlined high leaf CO2 assimilation, transpiration, carboxylation efficiency, and chlorophyll content in plants grown under Si supplying and well-watered conditions. The negative impact of water deficit on leaf gas exchange was alleviated by Ca2SiO4 application, but the instantaneous water use efficiency was maintained as similar in both water regimes, as expected for Si non-accumulator species. Morphologically, coffee stem diameter was increased under Ca2SiO4 application, regardless of water regime. In conclusion, our data revealed that high Ca2SiO4 doses benefit coffee performance and also suggest that the use of steel slag—an industrial byproduct rich in Ca2SiO4—can be considered as a sustainable practice for residue recycling in agriculture while improving C. arabica growth and physiology under varying water availability.

It has been shown that pollen as a dietary supplement may increase the establishment (development and reproduction) and survival of phytoseiid predatory mites, and therefore the pest control these mites can provide. In this study, the role of apple pollen as a supplemental food source was assessed as a means to increase the efficiency of two predatory mite species, Neoseiulus cucumeris and Amblyseius swirskii, for control of western flower thrips, Frankliniella occidentalis, under greenhouse conditions. The impact of apple pollen on thrips populations and predator establishment on a greenhouse chrysanthemum crop was determined over a 4-week period. The two mite species were released separately and in combination with and without pollen with two control treatments (thrips only and thrips + pollen). The introduction of A. swirskii together with pollen application provided the best control of thrips (adults and immatures). The establishment of N. cucumeris was very low in the crop during the greenhouse trial. This could be attributable, in part, to their response to extreme temperature ranges that were encountered during the greenhouse cage trials. The use of A. swirskii alone and the mixed population of the two predatory mite species without pollen resulted in the lowest frequencies of plants with heavy damage, followed by the same treatments with the addition of apple pollen.

Free-living astigmatid mites include numerous stored-product pests of economic importance, some of which are also widely used as factitious foods for the mass rearing of predatory mites in biological control programmes. However, these pest species may pose health risks due to their allergenic properties. Consequently, plant-inhabiting astigmatid mites that are less harmful have been proposed as potential alternative factitious foods, although they remain poorly studied. This study evaluated two leaf-inhabiting astigmatids, Tyrophagus curvipenis (Acaridae) and Czenspinskia transversostriata (Winterschmidtiidae), as potential diets for two predatory mites Amblydromalus limonicus and Neoseiulus cucumeris (Phytoseiidae)—both widely used in biocontrol. Egg hatching rates reached 98% in all treatments for both predator species. However, prey species had a strong influence on survival, development, and reproduction of these phytoseiid mites. Amblydromalus limonicus showed low larval survival (30.6%) on T. curvipenis and failed to develop beyond the protonymph stage, whereas its survival rate on C. transversostriata exceeded 90%. Neoseiulus cucumeris successfully developed on both prey species, although its survival rates were slightly reduced (by 6.5%) and developmental time increased by half a day on T. curvipenis compared to C. transversostriata. On C. transversostriata, A. limonicus reached maturity faster than N. cucumeris (1.2 days faster in females, while 0.6 days faster in males). Overall reproductive performance was highest for N. cucumeris reared on C. transversostriata, with the shortest preoviposition period of 1 day, total fecundity of 40 eggs per female over a period of 18 days, or 2.2 eggs per day, indicating this species represents a superior factitious diet for N. cucumeris. Although T. curvipenis is not a suitable diet for A. limonicus, C. transversostriata is an excellent food for A. limonicus, which started to lay an average of 2 eggs per day for 15 days after a preoviposition period of 2 days. In conclusion, C. transversostriata supported high survival, rapid development, and good reproduction in both predatory mites, whereas T, curvipenis was unsuitable for A. limonicus. These results identify C. transversostriata as a promising, safer factitious diet for mass rearing of these phytoseiid in biological control.

In this study, we tested the effects of mechanical leaf removal, insecticide application, and their interaction on leafhoppers and phytophagous and predatory mites occurring in two vineyards over three growing seasons. Leaf removal was performed in the fruit zone using a two-head pulsed air leaf remover, while insecticides were applied with a tunnel air-assisted sprayer at the maximum dose/ha recommended on the product label. Results demonstrated the efficacy of insecticide application in reducing the population densities of leafhoppers but also their detrimental effects on predatory mites. In a number of case studies, leaf removal reduced leafhopper and predatory mite densities. In one vineyard, phytophagous mite populations increased some weeks after leaf removal and insecticide application, highlighting the need to carefully consider the potential impact of vineyard management practices on non-target arthropods in the IPM framework.