RELATIONSHIPS BETWEEN THE PARASITOID HYPOSOTER EXIGUAE AND THE CABBAGE LOOPER, TRICHOPLUSIA NI: THE EFFECT OF HOST AGE ON OVIPOSITIONAL RATE OF THE PARASITOID AND SUCCESSFUL PARASITISM

1975 ◽  
Vol 107 (7) ◽  
pp. 689-694 ◽  
Author(s):  
Zane Smilowitz ◽  
Gerard F. Iwantsch
Keyword(s):  
Trichoplusia Ni ◽  
Cabbage Looper ◽  
Host Age ◽  
Older Individuals ◽  
Percentage Parasitism ◽  
First Instar ◽  
Third Instar Larvae

AbstractThe effect of host age of the cabbage looper, Trichoplusia ni (Hübner), on ovipositional rate and successful parasitism by Hyposoter exiguae (Viereck), a solitary endoparasitoid was investigated. Success in parasitism of T. ni was correlated with host age. Successful parasitism of hosts exposed as first, second, or early third instar larvae, ranged from 83 to 88%. A decline in parasitism was observed for the remaining instars with a low of 27% for mid-fifth instar larvae.A different relationship between host age and successful parasitism was observed in tests where all five instars of the host were presented to the parasitoid simultaneously. Successful parasitism was highest among second and third instars, approximately 75% for both, and lowest for fifth and first instars, 10% and 30%, respectively. A significantly higher rate of mortality was found for first instar hosts.The ovipositional rate of H. exiguae was related to host age. The parasitoid deposited an average of 2.3 and 1.3 eggs per 24 h in first and second instar T. ni, respectively The number of eggs/host and degree of superparasitism declined in older individuals and differed statistically for each instar. The percentage parasitism differed statistically for all but first and second instar larvae.

RELATIONSHIPS BETWEEN THE PARASITOID HYPOSOTER EXIGUAE AND THE CABBAGE LOOPER, TRICHOPLUSIA NI: EFFECTS ON HEAD-CAPSULE WIDTH, LIVE AND DRY WEIGHTS, AND HEMOLYMPH SPECIFIC GRAVITY OF HOSTS AT DIFFERENT AGES

1975 ◽  
Vol 107 (9) ◽  
pp. 927-934 ◽  
Author(s):  
Gerard F. Iwantsch ◽  
Zane Smilowitz
Keyword(s):  
Specific Gravity ◽  
Trichoplusia Ni ◽  
Dry Weight ◽  
Head Capsule ◽  
Cabbage Looper ◽  
Host Age ◽  
Head Capsule Width ◽  
Growth Increments ◽  
Developmental Parameters

AbstractThe effects of parasitism by Hyposoter exiguae (Viereck) on certain developmental parameters of Trichoplusia ni (Hübner) were influenced by host age at parasitism.Head-capsule growth increments for parasitized Trichoplusia ni became smaller with each successive molt during parasitism so that determination of instar on the basis of head-capsule width became impossible.Parisitized T. ni showed a proportionately smaller gain in weight from time of stinging until parasitoid emergence the older they were when stung (6 times for 3rd instars; 2 times for 4th instars; and no gain for 5th instars). This retardation was evident 24 h after parasitism. Essentially the same results were obtained for dry weight.Percentage dry weight of parasitized larvae tended to increase over control values until the 5th stadium when controls abruptly increased. Values for parasitized 5ths remained below the controls. Values found on the last days reflected those of the parasitoid which composed most of the mass inside the host cuticle.Hemolymph specific gravity in controls and parasitized 3rd instars oscillated with a frequency of one stadium in the 3rd, 4th, and early 5th stadia. Specific gravity of controls then rose to a maximum of 1.0501 in the prespinning phase and dropped by the pharate–pupal phase. Values for parasitized larvae in the 5th stadium rose slightly before leveling off, and parasitized 5th instars rose to a maximum on the next-to-last day. Maximum values attained for hosts parasitized as 3rd and 5th instars never reached that for controls on day 11. This may be related to the complete unacceptability or unsuitability of T. ni larvae for parasitism from day 11 on.

scholarly journals Antagonism between Cry1Ac1 and Cyt1A1 Toxins ofBacillus thuringiensis

1999 ◽  
Vol 65 (5) ◽  
pp. 2049-2053 ◽  
Author(s):  
M. Cristina del Rincón-Castro ◽  
José Barajas-Huerta ◽  
Jorge E. Ibarra
Keyword(s):  
Trichoplusia Ni ◽  
Cabbage Looper ◽  
First Instar ◽  
Ofbacillus Thuringiensis ◽  
High Concentrations ◽  
Different Strains ◽  
Parasporal Crystals ◽  
Very High

ABSTRACT Most strains of the insecticidal bacterium Bacillus thuringiensis have a combination of different protoxins in their parasporal crystals. Some of the combinations clearly interact synergistically, like the toxins present in B. thuringiensis subsp. israelensis. In this paper we describe a novel joint activity of toxins from different strains ofB. thuringiensis. In vitro bioassays in which we used pure, trypsin-activated Cry1Ac1 proteins from B. thuringiensissubsp. kurstaki, Cyt1A1 from B. thuringiensissubsp. israelensis, and Trichoplusia niBTI-Tn5B1-4 cells revealed contrasting susceptibility characteristics. The 50% lethal concentrations (LC50s) were estimated to be 4,967 of Cry1Ac1 per ml of medium and 11.69 ng of Cyt1A1 per ml of medium. When mixtures of these toxins in different proportions were assayed, eight different LC50s were obtained. All of these LC50s were significantly higher than the expected LC50s of the mixtures. In addition, a series of bioassays were performed with late first-instar larvae of the cabbage looper and pure Cry1Ac1 and Cyt1A1 crystals, as well as two different combinations of the two toxins. The estimated mean LC50 of Cry1Ac1 was 2.46 ng/cm2 of diet, while Cyt1A1 crystals exhibited no toxicity, even at very high concentrations. The estimated mean LC50s of Cry1Ac1 crystals were 15.69 and 19.05 ng per cm2 of diet when these crystals were mixed with 100 and 1,000 ng of Cyt1A1 crystals per cm2 of diet, respectively. These results indicate that there is clear antagonism between the two toxins both in vitro and in vivo. Other joint-action analyses corroborated these results. Although this is the second report of antagonism between B. thuringiensis toxins, our evidence is the first evidence of antagonism between toxins from different subspecies of B. thuringiensis (B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. israelensis) detected both in vivo and in vitro. Some possible explanations for this relationship are discussed.

FACTORS AFFECTING INFECTIVITY OF VAIRIMORPHA NECATRIX (MICROSPORIDIA: NOSEMATIDAE) IN TRICHOPLUSIA NI (LEPIDOPTERA: NOCTUIAE)

1981 ◽  
Vol 113 (2) ◽  
pp. 93-102 ◽  
Author(s):  
Wei Hsuang Chu ◽  
Robert P. Jaques
Keyword(s):  
Trichoplusia Ni ◽  
Cabbage Looper ◽  
Artificial Light ◽  
Disease Development ◽  
Optimum Temperature ◽  
Factors Affecting ◽  
Rate Of Development ◽  
Time To Death ◽  
Third Instar Larvae

AbstractIngested dosages of 10.9 and 16.5 spores of Vairimorpha necatrix (Kramer) 7 and 27 weeks old, respectively, killed 50% of third-instar larvae of the cabbage looper, Trichoplusia ni (Hübner). Time to death of 50% of larvae (LT50) decreased from 14 to 3 days with increases in dosage from 5 × 101 to 5 × 106 spores (2-week-old)/Iarva. The LT50 for 5 × 101 spores/larva increased from 14 to 25 days with storage of spores at 4°C for 2 and 93 weeks, respectively. Spores applied to soil lost little activity during cool weather but spores applied in summer were inactivated within 60 days. Desiccation or exposure to sunlight or artificial light inactivated the spores. Rate of development of disease was increased by feeding host larvae a diet containing increased proportions of casein or sucrose. The optimum temperature for disease development in T. ni was 25°C.

Effects of host plant,Gossypium hirsutum L., on sexual attraction of cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae)

1994 ◽  
Vol 20 (11) ◽  
pp. 2959-2974 ◽  
Author(s):  
P. J. Landolt ◽  
R. R. Heath ◽  
J. G. Millar ◽  
K. M. Davis-Hernandez ◽  
B. D. Dueben ◽  
...  
Keyword(s):  
Gossypium Hirsutum ◽  
Host Plant ◽  
Trichoplusia Ni ◽  
Sexual Attraction ◽  
Cabbage Looper ◽  
Gossypium Hirsutum L ◽  
Lepidoptera Noctuidae

The Hydraenidae of Cuba (Insecta: Coleoptera) II: Morphology of preimaginal stages of six species and notes on their biology

Zootaxa ◽  
2017 ◽  
Vol 4238 (4) ◽  
pp. 451 ◽  
Author(s):  
ALBERT DELER-HERNÁNDEZ ◽  
JUAN A. DELGADO
Keyword(s):  
Instar Larva ◽  
Morphological Characters ◽  
Larval Instars ◽  
First Instar ◽  
Preimaginal Stages ◽  
First Time ◽  
Third Instar Larvae

Preimaginal stages of the six species of Hydraenidae presently known from Cuba were obtained by rearing adults in the laboratory. Eggs of Hydraena perkinsi Spangler, 1980, H. decui Spangler, 1980 and H. franklyni Deler-Hernández & Delgado, 2012 are described and illustrated for the first time. The first instar larva of Gymnochthebius fossatus (LeConte, 1855) is redescribed, adding some new remarkable morphological characters including what could be the first abdominal egg-burster reported for this family. All larval instars of H. perkinsi, H. guadelupensis Orchymont, 1923 and Ochthebius attritus LeConte, 1878 are described and illustrated for the first time, with a special emphasis on their chaetotaxy. The second instar larva of G. fossatus along with first and third instar larvae of H. decui and H. franklyni are also studied for the first time. The pupal morphology and vestiture of a species belonging to the genus Hydraena are described for the first time, based on the pupa of H. perkinsi. Biological notes for several preimaginal stages of the studied species are also given. 

scholarly journals Carrageenans, Sulphated Polysaccharides of Red Seaweeds, Differentially Affect Arabidopsis thaliana Resistance to Trichoplusia ni (Cabbage Looper)

PLoS ONE ◽  
2011 ◽  
Vol 6 (10) ◽  
pp. e26834 ◽  
Author(s):  
Jatinder S. Sangha ◽  
Wajahatullah Khan ◽  
Xiuhong Ji ◽  
Junzeng Zhang ◽  
Aaron A. S. Mills ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Trichoplusia Ni ◽  
Cabbage Looper ◽  
Sulphated Polysaccharides ◽  
Red Seaweeds
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