The egg parasitoids Trichogramma: from laboratory mass rearing to biological control of lepidopteran pests

AbstractThelytokous Wolbachia-infected Trichogramma spp. are widely used egg parasitoids against lepidopteran pests in biological control programs. Wolbachia may manipulate host wasps for superparasitism and is sensitive to temperature. To explore effects of temperature and superparasitism, we compared fitness parameters and Wolbachia-mediated phenotype of thelytokous Wolbachia-infected Trichogramma dendrolimi between those emerging from superparasitised or single-parasitised hosts at 17, 21, 25, or 29 °C. Infected mothers of T. dendrolimi showed reduced superparasitism and parasitism increased with temperature. Wolbachia titre decreased with temperature when females emerged from singly-parasitised hosts, but there was no correlation in superparasitised hosts. Females showed higher Wolbachia titres at 21, 25, or 29 °C when developing from superparasitised hosts. The daily male ratio of offspring increased with temperature, and the day-age threshold for 5%, 50%, or 95% daily male ratio decreased with temperature in both parasitism forms. Females that emerged from superparasitised hosts had a shorter life span and reduced fecundity. These results indicate that Wolbachia may affect host behaviour by increasing superparasitism to enhance its spread, but this has negative effects on thelytokous Wolbachia-infected T. dendrolimi.

Download Full-text

Trichogramma: an egg parasitoid of crop pests

Bhartiya Krishi Anusandhan Patrika ◽

10.18805/bkap94 ◽

2018 ◽

Vol 33 (01) ◽

Author(s):

Omprakash Navik ◽

Richa Varshney

Keyword(s):

Biological Control ◽

Organic Farming ◽

Biocontrol Agent ◽

Egg Parasitoid ◽

Egg Parasitoids ◽

Time Cost ◽

Crop Pests ◽

Lepidopteran Pests ◽

Cost Of Protection

Use of insecticides to manage the emerging pest problems in the different crop being taken by farmers in their field. Today, due to indiscriminate use of insecticide, the agriculture produces getting contaminated and traced in food channel. For the reason, many farmers moving towards organic farming to produce pesticide free foods. In this context, control of emerging pest problem through biological control could be the better alternative. The egg parasitoids, Trichogramma being a major and efficient biocontrol agent for management of major lepidopteran pests in different corps. In India, great diversity of Trichogramma reported, hence, use of these egg parasitoids can cut the insecticidal application and same time cost of protection of farmers.

Download Full-text

Integrative taxonomy and phylogeography of Telenomus remus (Scelionidae), with the first record of natural parasitism of Spodoptera spp. in Brazil

Scientific Reports ◽

10.1038/s41598-021-93510-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ana P. G. S. Wengrat ◽

Aloisio Coelho Junior ◽

Jose R. P. Parra ◽

Tamara A. Takahashi ◽

Luis A. Foerster ◽

...

Keyword(s):

Biological Control ◽

Mitochondrial Gene ◽

First Record ◽

Mass Rearing ◽

Classical Biological Control ◽

Egg Parasitoid ◽

Integrative Approach ◽

Agricultural Pests ◽

Telenomus Remus ◽

Natural Parasitism

AbstractThe egg parasitoid Telenomus remus (Hymenoptera: Scelionidae) has been investigated for classical and applied biological control of noctuid pests, especially Spodoptera (Lepidoptera: Noctuidae) species. Although T. remus was introduced into Brazil over three decades ago for classical biological control of S. frugiperda, this wasp has not been recorded as established in corn or soybean crops. We used an integrative approach to identify T. remus, combining a taxonomic key based on the male genitalia with DNA barcoding, using a cytochrome c oxidase subunit I mitochondrial gene fragment. This is the first report of natural parasitism of T. remus on S. frugiperda and S. cosmioides eggs at two locations in Brazil. We also confirmed that the T. remus lineage in Brazil derives from a strain in Venezuela (originally from Papua New Guinea and introduced into the Americas, Africa, and Asia). The occurrence of T. remus parasitizing S. frugiperda and S. cosmioides eggs in field conditions, not associated with inundative releases, suggests that the species has managed to establish itself in the field in Brazil. This opens possibilities for future biological control programs, since T. remus shows good potential for mass rearing and egg parasitism of important agricultural pests such as Spodoptera species.

Download Full-text

Rearing Trissolcus japonicus and Trissolcus mitsukurii for Biological Control of Halyomorpha halys

Insects ◽

10.3390/insects11110787 ◽

2020 ◽

Vol 11 (11) ◽

pp. 787

Author(s):

Giuseppino Sabbatini-Peverieri ◽

Christine Dieckhoff ◽

Lucrezia Giovannini ◽

Leonardo Marianelli ◽

Pio Federico Roversi ◽

...

Keyword(s):

Biological Control ◽

Control Method ◽

Egg Parasitoids ◽

Halyomorpha Halys ◽

Progeny Production ◽

Asian Origin ◽

Frequent Use ◽

Trissolcus Japonicus ◽

Cumulative Curves

Halyomorpha halys is a severe agricultural pest of Asian origin that has invaded many countries throughout the world. Pesticides are currently the favored control methods, but as a consequence of their frequent use, often disrupt Integrated Pest Management. Biological control with egg parasitoids is seen as the most promising control method over the long-term. Knowledge of the reproductive biology under laboratory conditions of the most effective candidates (Trissolcus japonicus and Trissolcus mitsukurii) for optimizing production for field releases is strongly needed. Rearing of these egg parasitoids was tested by offering three different host supply regimes using new emerged females and aged, host-deprived females in different combinations. Results showed a mean progeny per female ranging from 80 to 85 specimens for T. japonicus and from 63 to 83 for T. mitsukurii. Sex ratios were strongly female biased in all combinations and emergence rates exceeded 94% overall. Cumulative curves showed that longer parasitization periods beyond 10–14 days (under the adopted rearing regimes) will not lead to a significantly increase in progeny production. However, ageing females accumulate eggs in their ovaries that can be quickly laid if a sufficient number of host eggs are supplied, thus optimizing host resources. Our data showed that offering H. halys egg masses to host-deprived female Trissolcus once a week for three weeks allowed its eggs to accumulate in the ovary, providing the greatest number of offspring within a three week span.

Download Full-text