Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) Parasitism of Trichoplusia ni (Lepidoptera: Noctuidae) Eggs Under Different Temperatures

Abstract

A study of the biological characteristics and thermal requirements of the parasitoid Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) on eggs of Trichoplusia ni (Hübner, 1802) (Lepidoptera: Noctuidae) at several different temperatures was performed in this work. Eggs of T. ni were exposed to T. pretiosum strain Tspd parasitism for 5 hr and then transferred to environmentally controlled growth chambers set at the temperatures of 18, 21, 24, 27, 30, and 33 ± 1°C. The duration of the T. pretiosum egg-to-adult period was affected by temperature, varying from 6 to 18 d over the range of the studied temperatures. The number of individuals emerged per egg and the sex ratio also were affected by temperature variations, but regression analysis did not find correlation between the increase of temperature and the observed variation of these biological parameters. Similarly, parasitism viability (percentage) was influenced by temperature variation, but always exceeded 80% at all tested temperatures. The thermal lower limit of development (Tbase) and the thermal constant (K) for T. pretiosum were 11.84°C and 128.37 DD, respectively. These results here reported indicate that T. pretiosum was impacted by the temperature, however, this parasitoid had a satisfactory performance on T. ni eggs at all studied temperature (from 18 to 33°C), showing potential to be used successfully as a biological control agent of this pest in different regions that fit in this tested temperature range. Also, the rearing temperature of this parasitoid might be changed from 18 to 33°C, according to commercial demands for accelerating or retarding mass production for field releases without damages to the parasitoid development.

Effect of Temperature on Life History and Parasitization Behavior of Trichogramma achaeae Nagaraja and Nagarkatti (Hym.: Trichogrammatidae)

“…The tendency of variation between temperatures was similar for both sexes, and differences in developmental time were not observed between T. achaeae females and males at all tested temperatures. Similar results have been published by other authors in biological studies of different Trichogramma species [30,35,58,72,73]. In our study, the egg to adult development of T. achaeae at 25 • C was completed in 8.83 d in E. kuehniella eggs, lower than the 10.4 d and 10.8 d recorded by Ghosh et al [51] and Manohar et al [52] in Corcyra cephalonica Stainton (Lepidoptera: Pyralidae) and T. absoluta eggs, respectively.…”

“…Likewise, it is known that the adult longevity and reproductive skills of Trichogramma spp. may change in accordance with the temperature [73] and host nutritional quality during the development [74] and food in the adult stage [77]. The fertility was maximum at the first 24 h after emergence of T. achaeae females, and no preoviposition period was detected at all tested temperatures, except at 15 • C. After the first day, the oviposition peak consistently declined until female death, being more notable at those temperatures in which fertility was highest.…”

“…A single parasitoid emerged per egg of E. kuehniella, however it was common to find up 2-3 emerging adults from C. chalcites eggs collected in banana crops [18,21]. These differences could be caused by the bigger size of C. chalcites eggs compared to E. kuehniella eggs and its nutritional quality for the parasitoid development [73]. Despite that, our findings clearly shown that E. kuehniella eggs can be considered an appropriate alternative host to support the development of T. achaeae.…”

The Effect of Host Density and Viability on Superparasitism Behavior of <i>Trichogramma cacoeciae</i> and <i>T. principium</i> Females

“…nr. curvimaculatus [12], [15], [22], [32], [33], Many species are able to distinguish between unparasitized and parasitized hosts ] 4 [ . Our results illustrated that both parasitoids tend to show a preference for certain host eggs and parasitized them repeatedly, this led in many instances to a host egg contained multiple parasitoid eggs (Figures 1 and 2).…”

Spraying Quality of Crop Protection Products Using Two Droplet Spectra in Three Periods of the Day

“…Unfortunately, during its cycle, these plants are subjected to the attack of pests and diseases, which may reduce productivity and quality. Chemical control is one of the most used techniques by farmers to control these damaging agents (Altoé et al, 2012). On the other hand, ineffective applications can generate losses to the farmer, ranging from the need for reapplications to a complete loss of the crop production potential.…”