scholarly journals Screening Coconut Cultivars for Tolerance to Infestation by the Coconut Mite, Aceria guerreronis (Keifer) in Sri Lanka

CORD ◽  
2014 ◽  
Vol 29 (1) ◽  
pp. 6
Author(s):  
L. Perera
Keyword(s):  
Sri Lanka ◽  
Control Method ◽  
Cocos Nucifera ◽  
Mite Infestation ◽  
Crop Loss ◽  
Field Observations ◽  
Aceria Guerreronis ◽  
Yield Data ◽  
Damage Initiation ◽  
Coconut Mite

The coconut mite (Aceria guerreronis Keifer) is a tiny pest which severely damages the nuts of the coconut palm (Cocos nucifera Linnaeus). At present there is no appropriate control method for this pest in Sri Lanka. Field observations have revealed difference in the severity of A. guerreronis mite infestation among selected and improved coconut cultivars in Sri Lanka. This difference has not been studied in depth and therefore the present study was conducted to investigate the levels of tolerance in selected and improved coconut cultivars and, if differences were demonstrated, to understand the mechanism behind the tolerance. A replicated trial in Thammenna Estate (TE) in Puttalam district in Sri Lanka, where the mite infestation was natural and severe, was selected for this study.  The trial was planted in 1983 and consisted of two improved coconut cultivars; Sri Lanka Yellow Dwarf x Sri Lanka Tall (YDT) and Sri Lanka Green Dwarf x Sri Lanka Tall (GDT) and the selected Sri Lanka Tall cultivar (TT) which has, green (TTG) and russet coloured (TTR) forms.  Population assessment of mites on immature nuts, damage initiation of the fourth bunch and harvest records were obtained. Further, characters that were thought to influence tolerance, such as nut shape as measured by ratio of length to breadth, the tightness of perianth to the nut surface and some changes in the affected tissues were also recorded. Yield data were collected for each cultivar to estimate the crop loss due to coconut mite damage. The results revealed that out of the cultivars tested in this trial, YDT had the lowest incidence of mite colonization and the smallest mite population size and symptom initiation compared to others. The distance between the perianth and nut surface, the least in YDT, is suggested as the most probable morphological feature that would impart tolerance to mite infestation.

scholarly journals Functional and numerical responses of the predatory mite Amblyseius aerialis (Acari: Phytoseiidae) to Aceria guerreronis (Acari: Eriophyidae)

Acarologia ◽  
2022 ◽  
Vol 62 (1) ◽  
pp. 27-35
Author(s):  
Camila Tavares Ferreira ◽  
Aloyséia Cristina da Silva Noronha ◽  
Eduardo Pereira Souza Neto ◽  
Raimundo Parente De Oliveira ◽  
Paulo Manoel Pontes Lins ◽  
...  
Keyword(s):  
Cocos Nucifera ◽  
Predatory Mite ◽  
Food Sources ◽  
Physical Barrier ◽  
Aceria Guerreronis ◽  
Coconut Tree ◽  
Coconut Mite ◽  
The Mean ◽  
Pest Mite ◽  
Cocos Nucifera L

The coconut mite, Aceria guerreronis Keifer, is one of the main pests of the coconut tree (Cocos nucifera L.) worldwide. Its control is mainly based on the use of acaricides. However, due to the habitat of this pest mite, which is protected by fruit bracts that act as a physical barrier, chemical control is often inefficient. Thus, natural enemies have been studied as an alternative to acaricides. We evaluated the functional and numerical responses of Amblyseius aerialis (Muma) to increasing densities of A. guerreronis (40, 80, 160, 240 and 360) and additionally the oviposition rates of the phytoseiid A. aerialis over 11 days on different food sources: coconut pollen, A. guerreronis and a mix of pollen and A. guerreronis. Our results showed that Amblyseius aerialis showed a type III functional response, where prey consumption increasing as the density of A. guerreronis increased, with a maximum consumption of up to 175 prey per predator. All the prey densities allowed female oviposition. The number of eggs laid by A. aerialis increased with increasing prey density and stabilized between 240 and 360 A. guerreronis individuals, with an average oviposition of 1.7 eggs/female. Furthermore, our results showed that all the food sources (coconut pollen, A. guerreronis and a mix of pollen and A. guerreronis) supported oviposition. The mean oviposition was approximately 1.5 eggs/female on all the food sources. Our study suggests that A. aerialis can be effective in the biological control of A. guerreronis. However, further studies are needed to investigate whether A. aerialis can explore the habitat of A. guerreronis and if that prey can support the development of immature stages and the reproduction of A. aerialis.

Evaluation of four isolates of Hirsutella thompsonii against coconut mite (Aceria guerreronis) in Sri Lanka

2007 ◽  
Vol 26 (7) ◽  
pp. 1062-1066 ◽  
Author(s):  
L.C.P. Fernando ◽  
P. Manoj ◽  
D.C.L. Hapuarachchi ◽  
S. Edgington
Keyword(s):  
Sri Lanka ◽  
Aceria Guerreronis ◽  
Coconut Mite ◽  
Hirsutella Thompsonii

scholarly journals Incidence and seasonal occurrence ofmites (Acari) on coconut inWestBengal, India*

Zoosymposia ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 82-85 ◽  
Author(s):  
DEBJANI BANERJEE ◽  
SALIL K. GUPTA
Keyword(s):  
West Bengal ◽  
Feeding Habits ◽  
Cocos Nucifera ◽  
Seasonal Occurrence ◽  
Yield Reduction ◽  
Aceria Guerreronis ◽  
Phytophagous Mites ◽  
Coconut Mite ◽  
One Year ◽  
Cocos Nucifera L

Coconut (Cocos nucifera L.) is an important crop in West Bengal, India. The coconut mite, Aceria guerreronis Keifer (Eriophyidae), is becoming a serious threat to its cultivation in that state. This mite lives underneath the perianth, attacking the epidermis and causing damage that leads to considerable yield reduction. The same habitat was found to be shared by several other mites during a one year study in a coconut orchard in South 24 Parganas District ofWest Bengal, in 2007–2008. In total, 11 species of nine families were found in this study, including mites of different feeding habits, but mainly predatory and phytophagous mites. Neoseiulus paspalivorus (De Leon) was the predominant predator, while A. guerreronis was the predominant phytophagous species. Both were found throughout the year. The highest abundance of those species occurred in April and June, respectively. The association of N. paspalivorus and A. guerreronis has been observed in different countries and in other parts of India.

scholarly journals Coconut destiny after the invasion of Aceria guerreronis (Acari: Eriophyidae) in India*

Zoosymposia ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 160-169 ◽  
Author(s):  
M. A. HAQ
Keyword(s):  
Management Practices ◽  
Critical Assessment ◽  
Bakery Products ◽  
Aceria Guerreronis ◽  
Agricultural Income ◽  
Northern India ◽  
Coconut Mite ◽  
Farming Community ◽  
The People ◽  
Considerable Damage

The coconut mite, Aceria guerreronis Keifer, has emerged as a common menace to most of the coconut plantations in India. After its first upsurge in Kerala at the end of the 1990´s, the mite has spread to many states in southern and northern India, causing considerable damage. Coconut provides one third of the agricultural income in the regions in which it is grown and more than 10 million people are dependent on this cash crop directly or indirectly through coconut-based industries like coir, copra, oil, honey, furniture, handicrafts, beverages, bakery products and so on. The economic instability of the coconut farming community and the people employed in coconut-based industries rank the highest order. A critical assessment of the various problems created by A. guerreronis in the agricultural economy of India is presented in order to supplement data on crop loss through nut malformation, nut fall, loss in fibre and copra. Varietal differences in susceptibility of the plant and future strategies in terms of management practices for an early control of the mite are discussed, and suggestions for future activities to alleviate mite damage are presented.

Drechslera incurvata. [Descriptions of Fungi and Bacteria].

1972 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Sri Lanka ◽  
Papua New Guinea ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
New Caledonia ◽  
Solomon Islands ◽  
Cocos Nucifera ◽  
New Guinea ◽  
French Polynesia ◽  
New Hebrides

Abstract A description is provided for Drechslera incurvata. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cocos nucifera. DISEASE: A leaf spot of young coconut (Cocos nucifera). The spots are at first small, oval, brown; enlarging and becoming pale buff in the centre with a broad, dark brown margin. In severe attacks the edges of leaves become extensively necrotic. GEOGRAPHICAL DISTRIBUTION: Apart from records from Jamaica and Seychelles the fungus has been reported only from S.E. Asia, Australasia and Oceania: British Solomon Islands, Fiji, French Polynesia, Malaysia (W., Sabah, Sarawak), New Caledonia, New Hebrides, Papua-New Guinea, Philippines, Sri Lanka, Vietnam and Thailand. TRANSMISSION: Presumably air dispersed.

scholarly journals Ages and ablation and accumulation rates from 14C measurements on Antarctic ice

1995 ◽  
Vol 21 ◽  
pp. 139-143 ◽  
Author(s):  
J.J. Van Roijen ◽  
K. van der Borg ◽  
A.F.M. De Jong ◽  
J. Oerlemans
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Ice Cores ◽  
Extraction Technique ◽  
Field Observations ◽  
Accumulation Rates ◽  
Yield Data ◽  
Surface Ice ◽  
In Situ Production

Shallow ice cores from an Antarctic blue-ice area at Scharffenbergbotnen were l4C-analyzed using a dry-extraction technique and accelerator mass spectrometry. The in situ production was determined from the 14CO component and used to deduce the natural 14CO2 component. The ages were measured at 10 000 ± 3000 BP. The accumulation and ablation rates determined from the in situ production are 7–20 and 10 cm a−1. respectively, showing agreement with field observations. The derived ages and air-yield data show a nearby origin for the surface ice.

Statistical Analysis of Field Experiments in Coconut Using Fewer Recordings

1993 ◽  
Vol 29 (2) ◽  
pp. 207-213
Author(s):  
T. S. G. Peiris
Keyword(s):  
Statistical Analysis ◽  
Sri Lanka ◽  
Treatment Effects ◽  
Field Experiments ◽  
Yield Data ◽  
The Cost ◽  
Term Field ◽  
Research Institute

SummaryCoconut is harvested at bimonthly intervals (six picks per year) in all field experiments carried out by the Coconut Research Institute in Sri Lanka. Because recording of individual picks is costly and time consuming, it is of interest to know whether or not recording can be restricted to fewer picks without prejudicing the results of experiments. Yield data from five long-term field experiments conducted at five different locations showed that the sum of the first, third and fifth picks could provide a good estimate of the sum of six picks. Yield recording can therefore be confined to these three picks and the cost and time of recording in an experiment reduced by 50%. These three picks can conveniently be used to assess treatment effects on total annual yield.Análisis estadístico del rendimiento de coco

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