300003-World Science Day For Peace And Development.pptx
Â
Status and scope of alternate hosts in crop pest management
1. STATUS AND SCOPE OF ALTERNATE HOSTS IN
CROP PEST MANAGEMENT
BY
P.MANIKANDAN
1st Ph.D Entomology
Chairman
Dr.V.Selvanarayanan
Professor in Entomology
4. IMPORTANCE OF ALTERNATE HOSTS IN CROP PEST
MANAGEMENT
1. Alternate hosts as reservoir for crop pests
2. Scope of alternate hosts as trap crops
3. Alternate hosts as natural refugia for B.t.
transgenic plants
4. Alternate hosts as food and shelter for
natural enemies
5. Alternate hosts as dead end hosts
Norris and kogan , 2005 4
5. 1.Alternate hosts as reservoir for crop
pests
⢠Weed as a hosts for different insect and mite
pests
⢠Weeds-primary producers
⢠Weeds-alternative hosts for crop pests when the
crop is absent or is not in a phenological state
suitable for the pest.
⢠Weed used as alternative hosts are located in the
crop field, adjacent noncropped land or even
within the ecoregion, distant from the crop field.
Norris and kogan , 2005 5
6. ⢠weeds can enhance or hinder arthropod fitness
within the crop field.
⢠Weed presence or absence may affect arthropod
survival- Crop canopy is suboptimal for the
arthropods.
⢠Weeds- Faster spreading of pest.
Norris and kogan , 2005 6
41. Giant foxtail -Setaria faberii
Quackgrass -Elytrigia repens
The stalk borer-Papaipema nebris
Levine et al., 1975 41
42. Alternate host as on Shelter
Rice water weevil Dallisgrass -Paspalum dilatatum
Blueberry maggot -Rhagoletis mendax
Palrang et al.,1994
Geddes et al.,1992 42
43. Nematodes
(Sunil et al., 2010)
weeds-slender amaranth old world diamond flower Tropic ageratum
sickle pod
balsam apple
little ironweed ivy gourd cut leaf ground cherry
43
45. Role of weeds in crop ecosystems
⢠Lead to increased pest populations
⢠Japanese beetles (Popillia japonica) in Soybean field(10 fold).
⢠Diabrotica barberi and D. virgifera virgifera in corn
⢠Flower thrips (Megalurothrips sjosdti) populations in cowpeas
(Vigna sinensis)
Hammond and Stinner., 1987
45
46. Scope of weed hosts as trap crops
shepherdâs purse
Capsella bursa-pastorisTwin cress-Coronopus didymus
Hedge mustard-
Sisymbrium officinale
Cameron et al., 2017
46
54. ⢠Weed plants those are growing naturally such
as Tridax procumbens, Ageratum sp,
Alternanthera sp., etc. which act as nectar
source for natural enemies.
Tridax procumbens Alternanthera sp
Pollen and Nectar provider
54
55. ⢠Pollen feeding by the predacious mite Euseius
(Amblyseius) finlandicus on poppy (Papaver
rhoeas) was reported by Broufas & Koveos
(2000)
Euseius finlandicus Poppy-Papaver rhoeas
55
56. ⢠Weeds differed in their ability to provide
additional food for Diadegma insulare, a
parasitoid of the Plutella xylostella ; wild mustard
(Brassica kaber), yellow rocket (Barbarea
vulgaris), and wild carrot (Daucus carota) were as
effective as honey-water mixture.
Daucus carotaYellow rocket
Idrius and graphius, 1995 56
57. ⢠Lambsquarters (Chenopodium album) and
common sowthistle did not provide nectar,
but the parasitoid used honeydew from
aphids feeding on the weeds.
Norris and kogan, 2005
57
Chenopodium album
58. As host provider
⢠Several native parasitoids are developed from
host larvae that live on smooth pigweed
(Amaranthus hybridus).
Tingle et al.,1978
58
Spodoptera spp Amaranthus hybridus
59. ⢠Parasitoids of Lygus spp. were found from
bugs living on several weeds.
Graham et al.,1986
59
60. ⢠The mymarid Anagrus epos, which uses the
blackberry leafhopper (Dikrella californica)
when the grape leafhopper (Erythoneura
elegantula) is not present.
Doutt and Nakata, 1973.
60
Anagrus epos Dikrella californicablackberry
61. Alternate host as Dead-End crops
⢠Yellowrocket, Barbarea vulgaris var. arcuata,
works as a dead-end trap crop for the
diamondback moth, Plutella xylostella.
Shelton et al., 2004
61
62. ⢠Sunn hemp, Crotalaria juncea, has also been
suggested as a dead-end trap crop for the
bean pod borer, Maruca testulalis .
62
Crotalaria juncea Maruca testulalis
64. Removal of weeds: Boon or Bane?
⢠Removing spiny amaranth (Amaranthus
spinosus)-beans (Phaseolus sp.) by cutworms.
Genung.,1959
64
Amaranthus spinosus
65. ⢠Reducing London rocket (Sisymbrium irio), and
other weeds, drove false chinchbug (Nysius
raphanus) to grapes (Vitis vinifera)
Barnes.,1970 65
London rocket false chinchbug
66. ⢠Burning weeds resulted in the migration of
blueberry maggot adults to production
blueberry fields.
Geddes.,1992
66
67. Natural enemies efficiency
⢠Prey eggs present in weed hosts may not be
recognised by parasitoids as like primary hosts
which results in fewer parasitized eggs.
⢠Percentage parasitization of the rice bug
(Leptocorisa oratorius) eggs laid on weeds
such as goosegrass (Eleusine indica) and jungle
rice (Echinochloa colona) was less than half
that of eggs laid on rice (Oryza sativa) plants .
Morrils and Almazon, 1990
67
68. ⢠Redstem filaree (Erodium cicutarium) and desert plantain
(Plantago ovata) are suitable hosts for the beet
leafhopper (Circulifer tenellus), but its mymarid egg
parasitoid does not function well on these species, with
the result that inundative biocontrol releases do not work
well when these two species represent much of the
vegetation.
Al-Wahaibi and Walker, 2000.
68
Redstem filaree Desert plantain
69. ⢠Interactions between soybeans and weeds
such as showy crotalaria (Crotalaria
spectabilis), sicklepod (Cassia obtusifolia), and
Florida beggarweed (Desmodium tortuosum)
resulted in reduced rates of attack on prey by
Geocoris punctipes.
⢠Carabid beetles were caught in herbicide-
treated than in untreated weedy plots,
although there were more carabid and
staphylinid larvae in the weedy plots .
69
Norris and Kogan, 2005
70. ⢠Problem in using as trap crop over population
development leads to field infestation.
⢠Using as dead-end crops is limited because of
lack of knowledge on more number of dead
end crops.
70
71. Conclusion
⢠Destruction of alternate hosts
⢠Trap crops
⢠Refugia
⢠Natural enemies conservation
⢠Dead end crops
⢠Two edged sword
71
