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Journal ArticleDOI

Parasitizations Levels and Temperature Tolerance of Rice Bug (Leptocorisa oratorius Fabricius) Egg Parasitoids: Mass Rearing for Biological Control

08 Jun 2018-International Journal on Advanced Science, Engineering and Information Technology (INSIGHT - Indonesian Society for Knowledge and Human Development)-Vol. 8, Iss: 3, pp 714-719
TL;DR: The main species of rice bug egg parasitoids found were Hadronotus leptocorisae and Ooencyrtus malayensis with parasitization levels in the lowlands of 6.4% and 2.2% and the foothills of 28.4 % and 3.1% respectively.
Abstract: The rice bug is a significant pest that attacks wet rice fields Rice bug egg parasitoids can be used as a biological control for this pest in the field. Successful parasitoid mass rearing in the laboratory depends on optimum temperatures to ensure the fitness of the adults that are introduced into the field. The objectives of this research were to determine the parasitization levels of rice bug egg parasitoids from two areas in West Pasaman Regency; one in the lowlands (Kinali 56 m asl) and the one at a higher altitude in the foothills (Talamau 47 m asl). Then the best temperature for parasitoid rearing was determined for the dominant parasitoid. A purposive sampling method was used for collecting the rice bug egg samples which were collected along 1 km transect lines in the rice fields. A descriptive method was used to report the parasitization levels. Rearing temperature treatments for the dominant rice bug egg parasitoids in the laboratory were 20 o C, 25 o C, 30 o C and one batch raised as a control with no temperature regulation. 20 replications were conducted for each treatment. The data were analyzed using Completely Randomized Design (Statistics 8). The main species of rice bug egg parasitoids found were Hadronotus leptocorisae and Ooencyrtus malayensis with parasitization levels in the lowlands of 6.4% and 2.2% and the foothills of 28.4 % and 3.1% respectively. The best temperature for mass rearing parasitoid in the laboratory was 25 o C, and they had the longevity of 22.6 ± 5.4 days.

Summary (2 min read)

Introduction

  • This in turn is influenced by biotic factors such as the size of parasitoids [1], the age of parasitoids, host density [2], and abiotic factors such as temperature [3],[4], relative humidity, rainfall [3],[5], and intensity of light [3].
  • Alydidae) in West Pasaman Regency, West Sumatra has not been studied although this pest is endemic in the area and effects every crop and can cause up to 50% yield loss, also known as (Hemiptera.
  • Grains attacked during the milky stage of growth become empty husks, decreasing the quality and quantity of hulled rice [6].
  • Discovering the species of rice bug egg parasitoids that occur in an area is the first step to determining whether they could be used for biological control there.

A. Collecting of Samples

  • The locations were sampled using purposive sampling and the rice bug eggs samples were collected along 1 km transect lines in rice fields.
  • The criteria for choice of locations were an area around 3-5 ha and rice at the milk stage of development.
  • The collected eggs were studied in the Insect Bioecology Laboratory, Plant Protection Department of Andalas University (220 m asl, relative humidity 85%-90%) from April 2016 until June 2016.
  • A descriptive method was used to characterize parasitization, mortality and natality levels.

B. Observation in Laboratory

  • The samples were collected and placed in one small test tube (1 cm diameter) per leaf with a single cluster of eggs in each test tube.
  • The authors identified each of the parasitoids that emerged under a binocular microscope Carton SPZ50 [8] [15] [16].
  • Once the dominant parasitoid was identified and the parasitization level measured.
  • Temperature tolerance was tested for this species, feeding them drops of honey on the inside of the test tube and observing them daily over their full lifespan.

A. Parasitization Level of Rice Bug Egg Parasitoids

  • Two parasitoid species were identified in both research locations ; Hadronotus leptocorisae and Ooencyrtus malayensis.
  • H. leptocorisae has been also found to be the dominant parasitoid in rice bug eggs at other West Sumatra locations i.e; at Pariaman Regency [17], Agam Regency [18], and Tanah Datar Regency [19].
  • More the eggs adhering [22] in leaf cause glue images (b).
  • A previous study [2] has shown that in the host egg Chillo sacchariphagus the quality and quantity of nutrients in the host larvae determines the success of the emergence of adult Xanthocampoplex sp. parasitoid.
  • Temperature also affects the growth and survival rate of adult E. argenteopilosus parasitoids which are more likely to emerge successfully at temperatures near 20oC.

B. Tolerance of Hadronotus leptocorisae Adult Parasitoids Towards Temperature

  • The relationship between temperature, parasitization levels and emergence percentage of H. leptocorisae was investigated using temperatures of 20oC, 25oC, 30oC, and uncontrolled room temperature.
  • The optimum temperature needed by adult parasitoids is dependent on species.
  • A b H. leptocorisae as the dominant rice bug egg parasitoid in West Pasaman Regency is a potential agent for biological control for rice bugs as part of an integrated pest management system as has been achieved in the Philippines.
  • F. Maulina, N. Nelly, Hidrayani, and H. Hamid, “Potensi pengembangan parasitoid telur walang sangit (Leptocorisa oratorius F.) di Kabupaten Padang Pariaman,” in Proc. Semnas.
  • Kebijakan dan pengembangan teknologi hilirisasi dalam upaya peningkatan nilai tambah produk pertanian, 2014, paper A, p 28-37. [18].

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Vol.
8
(201
8
) No.
3
ISSN: 2088
5334
Parasitizations Levels and Temperature Tolerance of Rice Bug
(Leptocorisa oratorius Fabricius) Egg Parasitoids: Mass Rearing
for Biological Control
Fri Maulina
#
, Novri Nelly
*
, Hidrayani
*
,
Hasmiandy Hamid
*
#
Department of Food Crop, Agricultural Polytechnic of Payakumbuh.
West Sumatra. 26271. Indonesia/Student of Agriculture Science Study
Program Post Graduate, Andalas University.
E-mail : maulinafri@yahoo.co.id
*
Department of Plant Protection, Agriculture Faculty. Andalas University. Padang. West Sumatra. 25163. Indonesia
E-mail: novrinelly@yahoo.com, hidrayani @yahoo.com, hasmiandyhamid@gmail.com
AbstractThe rice bug is a significant pest that attacks wet rice fields Rice bug egg parasitoids can be used as a biological control for
this pest in the field. Successful parasitoid mass rearing in the laboratory depends on optimum temperatures to ensure the fitness of
the adults that are introduced into the field. The objectives of this research were to determine the parasitization levels of rice bug egg
parasitoids from two areas in West Pasaman Regency; one in the lowlands (Kinali 56 m asl) and the one at a higher altitude in the
foothills (Talamau 47 m asl). Then the best temperature for parasitoid rearing was determined for the dominant parasitoid. A
purposive sampling method was used for collecting the rice bug egg samples which were collected along 1 km transect lines in the rice
fields. A descriptive method was used to report the parasitization levels. Rearing temperature treatments for the dominant rice bug
egg parasitoids in the laboratory were 20
o
C, 25
o
C, 30
o
C and one batch raised as a control with no temperature regulation. 20
replications were conducted for each treatment. The data were analyzed using Completely Randomized Design (Statistics 8). The
main species of rice bug egg parasitoids found were Hadronotus leptocorisae and Ooencyrtus malayensis with parasitization levels in
the lowlands of 6.4% and 2.2% and the foothills of 28.4 % and 3.1% respectively. The best temperature for mass rearing parasitoid
in the laboratory was 25
o
C, and they had the longevity of 22.6 ± 5.4 days.
Ke
ywordsegg parasitoid; Hadronotus leptocorisae; Ooencyrtus malayensis; parasitization; temperature; rice bug
I. INTRODUCTION
The effectiveness of parasitoids as pest control is
determined by the level of parasitization. This in turn is
influenced by biotic factors such as the size of parasitoids
[1], the age of parasitoids, host density [2], and abiotic
factors such as temperature [3],[4], relative humidity,
rainfall [3],[5], and intensity of light [3]. Use of parasitoids
as a biological control agent of rice/stinky bugs Leptocorisa
oratorius Fab. (Hemiptera : Alydidae) in West Pasaman
Regency, West Sumatra has not been studied although this
pest is endemic in the area and effects every crop and can
cause up to 50% yield loss. This pest attack always happens
every year (2009-2014) so that if the climatic conditions
support an explosion of the population will arise. Grains
attacked during the milky stage of growth become empty
husks, decreasing the quality and quantity of hulled rice [6].
Generally, farmers use synthetic insecticides to control
this insect which can increase insecticide resistance, and
lead to the extinction of natural enemies, leave a toxic
residue in the hulled rice, and in the environment. One less
problematic control is using naturally occurring parasitoids
to attack the rice bug eggs. The parasitoids that have been
found in eggs of rice bugs include Agrion sp or Hadronotus
leptocorisae [7],[8] and Ooencyrtus sp [9],[10], but nature of
the rice bug egg parasitoids in the area of West Pasaman
Regency, West Sumatra is still unknown. Discovering the
species of rice bug egg parasitoids that occur in an area is the
first step to determining whether they could be used for
biological control there. These rice bug egg parasitoids can
then be reared in large numbers in the laboratory and tested
in the field. If successful, continued mass rearing in a
controlled environment could lead to these parasitoids
becoming a sustainable biological control agent.
Previous researchers in Bandung, West Java [7] have
found that the females of H. leptocorisae egg parasitoid
prefer to lay eggs in 0-1 day old rice bug eggs. The female
parasitoid appears to be able to detect which of the rice bug
eggs are more likely to provide a favorable outcome for their
714

progeny select them over younger eggs. Its behaviour
associated with confidence of the parasitoid female to its
survival.
Temperature influences the development of both adult and
juvenile parasitoids and determines the success of mass
rearing activity in the laboratory., Temperature models have
been developed for Eriborus arganteopilosus parasitoid in
Crocidolomia pavonana larvae [4], and Ooencyrtus nezarae
parasitoid in Riptortus linearis eggs [11] to determine
optimum temperature for the development of the parasitoid
and so maximize the effectiveness and efficiency of mass
rearing. This model can predict the growth rate and
development of the parasitoid at different temperatures. [12]
has succeeded in using temperature control to extend the
longevity of the larvae stage of Eretmocerus mundus
parasitoids before they are released into the field. Methods to
predict tolerance limits for production of Oobius agrili,
Spathius agrili and Tetrastichus planipennisi parasitoids that
are fit to be released at particular locations including the
lower limits of temperature tolerance have been developed.
[13]. Developmental durations Aphelinus varipes (Forster)
parasitoid at mummies of Aphis glycines decreased with
increasing temperatures [14].
In this study, the level of parasitization of the dominant
species in rice bug eggs and the influence of temperature on
natality rates of the adult parasitoid in the laboratory is
investigated. Information from this study can be used to
plan strategic of mass rearing of the dominant parasitoid in
rice bug eggs. The objectives of this research were to
determine the parasitization levels of rice bug egg
parasitoids from two altitudes in West Pasaman Regency and
to determine the best temperature for rearing these
parasitoids in the laboratory.
II. MATERIAL AND METHOD
A. Collecting of Samples
The locations were sampled using purposive sampling and
the rice bug eggs samples were collected along 1 km transect
lines in rice fields. The criteria for choice of locations were
an area around 3-5 ha and rice at the milk stage of
development. The locations of research were in the
lowland (Kinali 56 m asl) and foothills (Talamau 547 m asl)
(Fig.1). The rice bug eggs were removed from rice leaves
and placed in a test tube with a lid (1 cm of diameter and 7
cm in length), and labeled.
Fig. 1 Location sample of the rice bug eggs from different locations in
West Pasaman, West Sumatra
The collected eggs were studied in the Insect Bioecology
Laboratory, Plant Protection Department of Andalas
University (220 m asl, relative humidity 85%-90%) from
April 2016 until June 2016. A descriptive method was used
to characterize parasitization, mortality and natality levels.
The dominant species of parasitoid was identified and
subsequently tested for survival at different temperatures
using Completely Randomized Design (Statistics 8) and 20
replications with temperatures of 20
o
C, 25
o
C, 30
o
C, and one
batch raised as a control with no temperature regulation.
B. Observation in Laboratory
The samples were collected and placed in one small test
tube (1 cm diameter) per leaf with a single cluster of eggs in
each test tube. We identified each of the parasitoids that
emerged under a binocular microscope Carton SPZ50 [8]
[15] [16]. Once the dominant parasitoid was identified and
the parasitization level measured. Temperature tolerance was
tested for this species, feeding them drops of honey on the
inside of the test tube and observing them daily over their
full lifespan.
C. Data Analysis
The data were calculated as follows:
1) Parasitization Levels
B
A
x 100% (1)
Notes:
P = Parasitization levels
A = Number of parasitoid eggs (emerging as
the healthy parasitoid, not emerging or abnormal)
B = Number of rice bug eggs in the sample
2) Mortality of Parasitoid
M = Pm x 100% (2)
Tp
Notes:
M = Mortality rate of parasitoids
Pm = Number of dead parasitoids (unable to emerge)
Tp = Total number of parasitoids
III. RESULTS AND DISCUSSIONS
A. Parasitization Level of Rice Bug Egg Parasitoids
Two parasitoid species were identified in both research
locations ; Hadronotus leptocorisae and Ooencyrtus
malayensis. H. leptocorisae being more dominant both in
lowland areas at 6.5 % parasitization levels and in the
foothills at 28.4 %. Parasitization levels of O. malayensis at
these sites were 3.1% and 2.21%, respectively. H.
leptocorisae has been also found to be the dominant
parasitoid in rice bug eggs at other West Sumatra locations
i.e; at Pariaman Regency [17], Agam Regency [18], and
Tanah Datar Regency [19].
It appears that H. leptocorisae thrives better in higher
altitudes although these figures may also be influenced by
the number of rice bug eggs which was higher in the
foothills (451 eggs along a 1 km transect) than the lowlands
(362 eggs along a similar transect) (Table I).
715

The same case was reported by [20] discovered that with
Diaeretiella rapae and Apidius sp, parasitoids of Lipaphis
erysimi, high populations of insect host in the field led to
higher parasitization levels. Recent laboratory research in
North Sumatra [2] indicated that the levels of parasitization
of the parasitoid Xanthocamploplex sp were influenced the
population density of the host (Chillo sacchariphagus
larvae). The highest level of parasitization observed in [2]
was 55%. Parasitization levels are reported to be influenced
by the availability of a supportive environment for the
development of the parasitoid, among others, the existence
of other plants that can provide temporary sustenance when
the conditions are not conducive main host plant. [21] found
the existence of the Arachis pintoi or Ageratum conyzoides
plants around a starfruit tree increased Fobius sp
parasitization of Bactrocera carambolae fruit flies.
The natality of H. leptocorisae that oviposited in the field
was found to be lower than in the laboratory. Mortality is
higher in the lowland eggs (87 %) compared to the foothills
(43 %) (Fig. 2). This further reinforces the notion that the H.
leptocorisae parasitoid requires relatively low temperatures
to thrive. Incidentally, temperatures were below average the
time of sampling (April 2016) due to rainfall with
precipitation at each of these locations being 334 mm and
438 mm respectively over this three month period (Table II).
Rice bug eggs are strongly attached (Fig.3) to the surface
of the rice leaves (a) even during rain. More the eggs
adhering [22] in leaf cause glue images (b). Nymph or adult
rice bugs on the rice plants are not so well protected and
washed away by heavy rains causing high mortality just as
has been observed in thrips and aphids on lettuce crops [25].
In fact, parasitoids appear to thrive in the lower
temperatures that accompany rainy periods. Many adult
parasitoids die as they attempt
to exit the host eggs (Fig.4).
Even perfectly formed adults were observed partial emerged
from chorion but become stuck and eventually died (a),
sometimes only one new antenna emerges before death (b).
The ovipositor of this parasitoid is visible indicating that the
body of a mature adult has been completely formed. The
observations under a binocular microscope showed that there
is no difference the morphology of the adult of H.
leptocorisae parasitoid between the live specimens and
those who die the eggs of the rice bug.
Fig. 2 Comparison of natality and mortality of Hadronotus leptocorisae egg
parasitoids in the laboratory in rice bug eggs from different locations in
West Pasaman, West Sumatra
A previous study [2] has shown that in the host egg Chillo
sacchariphagus the quality and quantity of nutrients in the
host larvae determines the success of the emergence of adult
Xanthocampoplex sp. parasitoid. But, in this case, the
condition of the nutrients in the L. oratorius eggs in this
study is thought to be sufficient for the growth and
development of the H. leptocorisae as the parasitoids are
perfectly formed as shown in figure 4.
Presumably, there are abiotic factors that influence the
ability of adult parasitoids to emerge from the host eggs.
Parasitoid oviposition and development to adulthood of H.
leptocorisae has been found to be more successful when the
host eggs are aged 0-1 days [7] as at this stage the egg is
incompletely formed and has poor body defense systems that
hinder emergence. There is not true for all parasitoids.
Xanthocamploplex sp parasitoids have been shown to be
more likely to be successful in infecting a 5-day old host [2],
was higher during the time of the study (Table II). The
temperature at this cooler location appears to be more
suitable for the development of the parasitoid. The inability
of adult parasitoid to emerge may also be influenced by
temperature. Temperature is one of the factors that influence
the development of the parasitoid (Trissolcus spp) on the
host (Eurygaster integriceps), especially on a lifespan and
oviposition period [5].
TABLE I
PARASITIZATION LEVEL OF PARASITOID IN RICE BUG EGGS ON PADDY CROP IN WEST
PASAMAN REGENCY, WEST SUMATRA
Location
(Subdistrict
/District)
Altitude
(m asl)
Number of Eggs
(eggs)
Parasitization of
Hadronotus leptocorisae*
(%)
Parasitization of
Ooencyrtus malayensis
(%)
Wonosari/Kinali 56 m asl (low
land )
362 6.50* 3.10
Banjar
Kuning/Talamau
547 m asl
(middle land)
451 28.40* 2.21
Note: *The dominant egg parasitoid in West Pasaman Regency, West Sumatra
716

Temperature has found to influence the abiltiy of Eriborus
argenteopilosus (Hymenoptera : Ichneumonidae) parasitoid
to emerge from Crocidolomia pavonanna (Lepidoptera :
Pyralidae) larvae [4]. Temperature also affects the growth
and survival rate of adult E. argenteopilosus parasitoids
which are more likely to emerge successfully at temperatures
near 20oC. At temperatures much higher or much lower
than 20oC the larvae do not develop in the pupae leaving
the pupae empty.
Fig. 3 The rice bug eggs adhering in paddy leaf: a. Eggs neatly arranged on
the leaves, b. there is glue on the surface under the egg
B. Tolerance of Hadronotus leptocorisae Adult Parasitoids
Towards Temperature
The relationship between temperature, parasitization
levels and emergence percentage of H. leptocorisae was
investigated using temperatures of 20
o
C, 25
o
C, 30
o
C, and
uncontrolled room temperature. Results indicate that 25
o
C
maximises longevity resulting in a lifespan of 22.6 ± 5.4
days which is significantly longer than at other temperatures
tested (Fig.5) indicating this is the temperature at which the
adult parasitoid thrives best. The 25
o
C temperature
treatment (B) gives a longevity significantly better than any
other treatment. This longevity indicates optimum conditions
for the development of the H. leptocorisae adult parasitoid.
The new result of reasearch [26] showed that the survival of
the egg of H. leptocorisae until adulthood in this
temperature was high (68.2%).
The highest insect activity also occurs at this temperature.
The optimum temperature needed by adult parasitoids is
dependent on species. The Aphelinus asychis (Walker)
parasitoid (Hymenoptera : Aphididae) of Aphis gossypii
(Glover) (Sternorrhyncha : Aphididae ) can adapt to
temperatures in the range 18-30
o
C, but reproduces better
when the temperature is close to 25
o
C [3]. Aenasius
bambawalei (Hayat) (Hymenoptera : Encyrtidae) parasitoid
of Phenacoccus solenopsis (Tinsley) (Hemiptera :
Pseudococcidae) thrives up to 27
o
C [22]. Parasitization
levels of Trissolcus semistriatus (Nees) in Eurygaster
integriceps (Put) is positively correlated with temperature up
to 20
o
C [6]. Temperature greatly affects the parasitization
success of Eriborus argenteopilosus [4]. Temperature
affects the intensity of the parasitoid’s activity in locating
and parasitizing the host. [24] showed that, along with
density of the host, a temperature of 2 C is best for
parasitoid success E. argenteopilosus in Crocidolomia
pavonana larvae. According to [25] temperature is the
driving force behind insect development, growth and
behavior. The local weather pattern a significant impact on
the abundance in an insect in our crops.
According to [3] the short development time, high female
to male ratio, long life span, and high fecundity, and
temperature tolerance are indications that a parasitoid may
be useful as a biological control agent. These features are
that are seen in H. leptocorisae. Using a parasitoid for
biological control requires prior mass rearing in a laboratory
and selecting the time of introduction into the field when the
environmental factors are most favorable. To provide
optimal laboratory conditions for this mass rearing of a
parasitoid in-depth study must be conducted including the
relationship between temperature and other abiotic factors
and the growth and reproduction of the parasitoid.
The insect's longevity is sensitive to environmental
variation. The number of eggs a parasitoid can oviposite on
the host eggs depends on longevity. The longevity of adult
of H. leptocorisae egg parasitoid is maximum at 25°C
(constant temperature) but the ideal values of other abiotic
factors such as humidity are yet to be determined.
Oviposition is most effective when the host eggs are aged
0-1 days as at this stage the adult parasitoids are more likely
to emerge successfully.
a
b
TABLE II
MORTALITY RELATIONSHIP WITH THE APPEARANCE OF HADRONOTUS LEPTOCORISAE EGG PARASITOIDS (DOMINANT PARASITOID)
IN WEST PASAMAN,WEST SUMATRA
Locations
(Sub-
district/District)
Altitude
(m asl)
Rainfall
(mm)
*
Egg Condition Pasca Oviposition Presentation of
Emerge
(%)
Un Emerge Emerge
Wonosari / Kinali 56 m asl (low
land )
334 20 3 13.0
Banjar Kuning/
Talamau
547 m asl
(middle land)
438 55 73 52.9
Note: *Rainfall on April 2016
717

Fig. 5 Effect of temperature for the longevity of Hadronotus
leptocorisae parasitoids in laboratory
H. leptocorisae as the dominant rice bug egg parasitoid in
West Pasaman Regency is a potential agent for biological
control for rice bugs as part of an integrated pest
management system as has been achieved in the Philippines.
U
nderstanding of local weather conditions before
introduction of the egg parasitoids that have been mass
reared in laboratory conditions will maximize impact. The
use of weather prediction tools such as CC-IS technology
that provides recommendations for planting and cropping
times would aid with this.
IV. CONCLUSION
H. leptocorisae was found to be the dominant rice bug
egg parasitoid present West Pasaman Regency. Comparison
of a lowland location and another in the foothills indicate it
appears to thrive better in higher altitudes and at lower
temperatures. Oviposition in young host eggs led to a higher
survival rate of the adult parasitoid which often died when
emerging from older host eggs. The optimum temperature
for laboratory raising of this parasitoid for biological control
was found to be 25
o
C as at this temperature the adult parasite
had an average lifespan of 22.6 ± 5.4 days. As an indigenous
natural enemy, it could play a larger role in an integrated
pest management system of rice bug pests in West Pasaman
and other similar tropical rice growing areas.
A
CKNOWLEDGMENT
We would like to thanks to the Director General of Higher
Education that gave me BPPDN scholarships with contract
number 8222/A4.2/KP/2015, so this research had been done
as well. The author would like to thank all those who helped
fulfilled the research process is particularly the students in
the collected sampling of rice bug eggs in West Pasaman
paddy field and laboratory technicians of Insect Bioecology
Laboratory of Agriculture Faculty, Andalas University,
Padang, West Sumatra.
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Journal ArticleDOI
TL;DR: Study of the land flooding effect before planting in controlling weed to yield components of several rice varieties showed that land flooding before planting affected the yield component of rice.
Abstract: Rice is the primary carbohydrate source for half world population, particularly for Asian people, and rice demand also increases for non-Asian people Rice provides the bulk daily calories for humans and animals One of the problems in SRI method is weed Many efforts to control weed in the SRI method and one of the way island flooding before planting The objective of the research was to study the land flooding effect before planting in controlling weed to yield components of several rice varieties The research was conducted in farmer land of Kuranji and Laboratory of Weed Science, Department of Crop Sciences, Faculty of Agriculture, Andalas University, Padang, West Sumatera, Indonesia from June to September 2019 A randomized block design was used in the experiment 5 rice varieties (Batang Piaman, Panca Redek, PB 42, Batang Pasaman, and Saganggam Panuah) were used as treatments The treatments were replied three times Generally, the result showed that land flooding before planting affected the yield component of rice For the length of the panicle, Panca Redek and Saganggam Panuah were the best variety (3018 cm and 2091 cm, respectively) For the weight of 1000 grains, Batang Piaman was the best variety (3567%), and Batang Piaman was also the best variety for the weight of dry grain (2833) For production per hectare, Batang Pasaman, Batang Piaman, and Saganggam Panuah were the best variety (504 ton, 492 to and 388 tons respectively)

3 citations


Cites background from "Parasitizations Levels and Temperat..."

  • ...The one factor that could decrease rice yield is the abiotic factor, and one of them is rice bug (Leptocorisa acuta, Hemiptera: Alydidae)[52][53]....

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Journal ArticleDOI
10 Oct 2016
TL;DR: Investigation of the effect of temperature and host density on superparasitisme by Eriborus argenteopilosus reveals that superparatism E. argenteopolosus was influenced by temperature andHost density.
Abstract: Effect of temperature and host density on superparasitisme by Eriborus argenteopilosus : Implication for biological control . Superparatism is a type of parasite in which the host is attacked by another parasitoid. Superparatism is influenced by several factors including temperature and host density. The aim of this research was to investigate the effect of temperature and host density on superparatism E. argenteopilosus . Different number of larva C. pavonana (15, 30, 60, 90 and 120) was infested with a female parasitoidat various temperature (200, 250, and 300C) for three hours. The larva host was disectionto enable us to count the number of eggs. The study result reveals that superparatism E. argenteopilosus was influenced by temperature and host density. Superparatism occured randomly at different temperature reaching the highest at 200 with host density of 15 and 30.

1 citations

Journal Article
TL;DR: Penelitian dilaksanakan di laboratorium Entomologi dan rumah kaca Jurusan Hama dan Penyakit Tumbuhan Fakultas Pertanian, Universitas Padjadjaran, Jatinangor, maka dicari cara penyimpanan yang dapat memperpanjang daya simpan pupa parasitoid yang lebih lama.
Abstract: Eretmocerus mundus adalah salah satu parasitoid yang berpotensi tinggi untuk dikembangkan sebagai agens pengendali hayati Bemisia tabaci. Salah satu kendala yang dijumpai dalam produksi massal parasitoid E. mundus adalah lama pupasi yang berkisar antara 3-4 hari, padahal untuk penanganan biakan massal sebelum parasitoid diaplikasikan atau dipasarkan perlu waktu penyimpanan yang lebih lama. Oleh karena adanya kendala dalam lama waktu penyimpanan pupa, maka dicari cara penyimpanan yang dapat memperpanjang daya simpan pupa parasitoid tersebut melalui penyimpanan pada suhu rendah di dalam lemari pendingin. Penelitian ini bertujuan untuk mengetahui lama waktu penyimpanan pupa parasitoid E. mundus pada suhu rendah terhadap tingkat kemunculan imago E. mundus dan tingkat parasitisasinya pada B. tabaci. Penelitian dilaksanakan di laboratorium Entomologi dan rumah kaca Jurusan Hama dan Penyakit Tumbuhan Fakultas Pertanian, Universitas Padjadjaran, Jatinangor. Metode yang digunakan adalah metode eksperimen dengan Rancangan Acak Lengkap (RAL) yang terdiri atas delapan perlakuan dan tiga ulangan. Kedelapan perlakuan tersebut adalah penyimpanan pias-pias yang berisi pupa parasitoid E. mundus. pada suhu rendah (5-9°C) selama 3, 6, 9, 12, 15, 18 dan 21 hari. Hasil penelitian menunjukan bahwa penyimpanan pupa E. mundus pada suhu rendah (5-9°C) dapat dilakukan sampai dengan 6 hari karena tidak mempengaruhi persentase kemunculan imago, lama muncul imago, tingkat parasitisasi dan lama hidup imago E. mundus. Kata kunci: Eretmocerus mundus, temperatur rendah, kebugaran, lama penyimpanan

1 citations

References
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Journal ArticleDOI
TL;DR: A three‐way analysis of variance revealed that egg load varies significantly with food or host access but not with parasitoid age, and it is confirmed that there is no egg resorption in V. canescens and that egg production stops in the absence of food.
Abstract: . The main effects and interactions of adult age, access to food and host deprivation, on the egg load of Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), a larval parasitoid of Ephestia kuehniella (Lepidoptera: Pyralidae) and other pyralids, were studied in the laboratory. Intraspecific variation in the number of ovarioles was also studied. There was a positive and significant correlation between wasp size and both egg load and ovariole number, with the reproductive system of large wasps containing significantly more ovarioles and mature eggs than small wasps. Newly emerged adult wasps contained 27 ± 2.4 ovulated (mature) eggs in their lateral oviducts. Access to food and host deprivation were the only conditions under which egg load increased with parasitoid age. Wasps that had access to hosts immediately after emergence showed a significant decline in their egg complement, irrespective of food presence. Under conditions of both host and food deprivation, there was practically no alteration of egg load with parasitoid age. A three-way analysis of variance revealed that egg load varies significantly with food or host access but not with parasitoid age. All interactions among the three factors were significant. It is confirmed that there is no egg resorption in V. canescens and that egg production stops in the absence of food.

51 citations

Journal ArticleDOI
TL;DR: A high tolerance to climatic variations and life cycle well adapted to this aphid host are properties that make it likely that A. asychis could be used for the biological control of the cotton aphid in greenhouses.
Abstract: The current laboratory study was designed to evaluate the effect of abiotic and biotic factors such as temperature, light intensity, relative humidity and host age on biological and ecological characteristics of Aphelinus asychis (Walker) parasitizing Aphis gossypii (Glover). The traits studied were developmental duration, mortality, sex ratio, longevity, fecundity and host feeding. A. asychis can completely develop and reproduce at temperatures 18°C and 30°C, light intensities of 1000 and 7000 lux and relative humidities of 30% and 60%. Temperature had a significant effect on the developmental duration as well as on the percentage and longevity of females, while mortality from mummification to emergence, fecundity and host feeding were only slightly affected. Relative humidity only affected the developmental duration of A. asychis. Light intensity had mostly affected the biological and ecological traits of A. asychis. High light intensity resulted in a shorter developmental duration, higher incidence of females and longer life span of the female parasitoid. A high tolerance to climatic variations and life cycle well adapted to this aphid host are properties that make it likely that A. asychis could be used for the biological control of the cotton aphid in greenhouses.

39 citations

Journal ArticleDOI
14 Jan 2016-PeerJ
TL;DR: The laboratory results showed that the successful parasitization rate of A. bambawalei increased with higher temperatures and older host stages, and the offspring sex ratio was clearly higher when the host stage was an adult female mealybug.
Abstract: Temperature and host stage are important factors that determine the successful development of parasitoids. Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) is a primary parasitoid of the newly invasive mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). The effects of temperature on the parasitic characteristics of A. bambawalei have seldom been investigated. In the study, we explored the effects of temperature, exposure time, and host stage on the parasitization rate and offspring sex ratio (female to male) of A. bambawalei under laboratory conditions. The laboratory results showed that the successful parasitization rate of A. bambawalei increased with higher temperatures and older host stages. When the parasitoids were exposed to 36 °C for 24 h, the parasitization rate of female adults (52%) was nearly two times that of 3rd instar nymphs. Additionally, heat stress duration and host stage resulted in an increase in the offspring sex ratio of A. bambawalei. When A. bambawalei was exposed to 36 °C for 24 h, the offspring sex ratio increased dramatically to 81.78% compared with those exposed for 12 h, and it increased to 45.34% compared with those exposed for 16 h. The offspring sex ratio was clearly higher when the host stage was an adult female mealybug Our findings provide important guidance for the mass rearing and field releases of A. bambawalei for the management of P. solenopsis in the future.

20 citations

Journal ArticleDOI
TL;DR: The potential of A. varipes as biological control agents is discussed by comparing them with Aphidius colemani Viereck, which has been introduced to horticultural crops in greenhouses in Japan.
Abstract: The development and reproductive potential of an indigenous parasitoid, Aphelinus varipes (Forster), was studied at 15, 17, 20, 25, and 30 °C. Developmental durations decreased with increasing temperatures. The emergence rate was higher than 90 % at 15, 17, and 20 °C. Offspring sex ratios were 0.69, 0.54, and 0.70 at 17, 20, and 25 °C, respectively, but were 0.14 at 15 °C and 0.38 at 30 °C. Developmental zeros of females and males were calculated as 9.9 and 9.6 °C, respectively. The effective accumulative temperature (K) was 204.1 degree-days in both sexes. Fecundity peaked in early age after emergence, then gradually decreased in a fluctuating manner at 20 and 25 °C. Host feeding continued constantly during the life of female adults at two temperatures. Single female parasitoids produced 218.5 and 203.1 mummies at 20 and 25 °C, respectively, during their lifespans. Aphids killed by parasitoid host feeding numbered 79.1 at 20 °C and 63.8 at 25 °C. Longevities were 27.0 days at 20 °C and 20.6 days at 25 °C. Moreover, intrinsic rates of natural increase (r m) were estimated as 0.151 at 20 °C and 0.227 at 25 °C. We discuss the potential of A. varipes as biological control agents by comparing them with Aphidius colemani Viereck, which has been introduced to horticultural crops in greenhouses in Japan.

11 citations


"Parasitizations Levels and Temperat..." refers background in this paper

  • ...Developmental durations Aphelinus varipes (Forster) parasitoid at mummies of Aphis glycines decreased with increasing temperatures [14]....

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Journal ArticleDOI

6 citations


"Parasitizations Levels and Temperat..." refers background in this paper

  • ..., Temperature models have been developed for Eriborus arganteopilosus parasitoid in Crocidolomia pavonana larvae [4], and Ooencyrtus nezarae parasitoid in Riptortus linearis eggs [11] to determine optimum temperature for the development of the parasitoid and so maximize the effectiveness and efficiency of mass rearing....

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Frequently Asked Questions (1)
Q1. What are the contributions in "Parasitizations levels and temperature tolerance of rice bug (leptocorisa oratorius fabricius) egg parasitoids: mass rearing for biological control" ?

Successful parasitoid mass rearing in the laboratory depends on optimum temperatures to ensure the fitness of the adults that are introduced into the field. The objectives of this research were to determine the parasitization levels of rice bug egg parasitoids from two areas in West Pasaman Regency ; one in the lowlands ( Kinali 56 m asl ) and the one at a higher altitude in the foothills ( Talamau 47 m asl ).