scholarly journals Release strategies of Amblyseius womersleyi and population dynamics of Amblyseius womersleyi and Tetranychus urticae: II. Test of two release rates on apple

2004 ◽  
Vol 39 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Chuleui Jung ◽  
Sanghyun Han ◽  
Joon-Ho Lee
Keyword(s):  
Population Dynamics ◽  
Tetranychus Urticae ◽  
Release Rates ◽  
Amblyseius Womersleyi

Predation by Euseius scutalis (Acari: Phytoseiidae) on Tetranychus urticae and Eutetranychus orientalis (Acari: Tetranychidae): effect of prey density and developmental stage

2021 ◽  
Author(s):  
Theodoros I. Stathakis ◽  
Eleftheria V. Kapaxidi ◽  
Georgios Th. Papadoulis ◽  
Nikos E. Papanikolaou
Keyword(s):  
Developmental Stage ◽  
Tetranychus Urticae ◽  
Prey Density ◽  
Spider Mite ◽  
Handling Time ◽  
Agricultural Pests ◽  
Release Rates ◽  
Density Dependent Mortality ◽  
Euseius Scutalis ◽  
Two Spotted Spider Mite

Predation ability is a key component determining the suppression of agricultural pests by natural enemies. The aim of this study is to evaluate the effect of prey density and developmental stage on the predation of Euseius scutalis (Acari: Phytoseiidae) on the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) and the oriental red mite, Eutetranychus orientalis (Acari: Tetranychidae). For this purpose, laboratory functional response experiments were conducted using female adults of E. scutalis. Results indicated that the predator causes an inverse density dependent mortality to larvae, nymphs and adults of the two-spotted spider mite, as well as the oriental red mite. The random predator equation was used to fit the data. E. scutalis handling time increased significantly with T. urticae and E. orientalis developmental stage. The maximum number of T. urticae prey consumed was 48.3 larvae, 28.5 nymphs and 11.0 adults, where the corresponding values for E. orientalis were 48.8, 32.2 and 18.2 larvae, nymphs and adults, respectively. Estimated handling times and attack rates of E. scutalis on larvae, nymphs and adults of T. urticae were 0.4970 h and 0.1058 h-1, 0.8435 h and 0.1395 h-1, and 2.1834 h and 0.0835 h-1, respectively. The corresponding values on larvae, nymphs and adults of E. orientalis were 0.4920 h and 0.1166 h-1, 0.7452 h and 0.1361 h-1, and 1.3186 h and 0.0597 h-1, respectively. The results of this study may be indicative of the predation ability of adults of E. scutalis on these notorious pests, providing a basis for determining release rates appropriate for various pest densities.

scholarly journals POPULATION DYNAMICS OF THE MICROBIOTA IN THE LITTER OF TWO TREE SPECIES OF THE ATLANTIC FOREST

FLORESTA ◽  
2020 ◽  
Vol 50 (3) ◽  
pp. 1449
Author(s):  
Fabiana Rodrigues Baldez ◽  
Marcos Gervasio Pereira ◽  
Tatiana Saldanha ◽  
Wilbert Valkinir Cabreira ◽  
Cristiane Figueira Da Silva ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Litter Decomposition ◽  
Atlantic Forest ◽  
Release Rate ◽  
Tree Species ◽  
Abiotic Factors ◽  
Nutrient Release ◽  
Release Rates ◽  
Litter Bags ◽  
P Release

This study analyzes microbiota population dynamics as a function of nutrient release rate during litter decomposition. For that, we observed two tree species native to the Atlantic Forest: brazilwood (Paubrasilia echinata) and inga (Inga laurina). To assess nitrogen (N), phosphorus (P), and potassium (K) release rates from the litter, we performed six collections over 365 days. In these collections, we placed polyvinyl bags called ‘litter bags’ below the treetops of the chosen species to collect dry leaves. To identify the groups of litter microorganisms (fungi, bacteria, and actinomycetes), we used the plate culture method to count the number of colony-forming units (CFU), and the fatty acid profile method, through biomarkers, associating nutrient release rate and abiotic factors (temperature and rainfall). Nutrient release rate correlates with litter decomposition at 140 days, and most microorganisms correlate with litter decomposition at 30 days. Nitrogen and phosphorus release rates correlate with rainfall. Fungi correlate with P release rate in inga litter decomposition. The bacteria biomarker 17:1 was the only one that correlated with N and P release rates. In conclusion, rainfall affects nutrient solubilization in the studied species, and microbiota differs between the species. When comparing the two methods to identify these microorganisms, information from one method complements information from the other, since both provide different but interdependent data.

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