Effects of Dehumidification on the Survivorship of Four Psocid Species

Psocids are damaging stored-product pests. In this study, eggs and early-instar nymphs, adults, and all life stages of Liposcelis entomophila, L. decolor, L. bostrychophila, and L. paeta were subjected to 43, 50, or 75% (Control) relative humidity (RH) for 2, 4, 6, 8, 10, 12, 14, or 16 d at 30.0°C. All adults of these species died within 8 d at both 43 and 50% RH, except for L. bostrychophila, which required 12 d at 50% RH for 100% mortality to occur. For all life stages and eggs and early-instar nymphs, maximum survival times (times to 100% mortality) at 43 or 50% RH for L. entomophila, L. decolor, L. bostrychophila, and L. paeta, were 8 and 10 d, 8 and 12 d, 12 and 14 d, and 12 and 16 d, respectively. During this study, numbers of nymphs and adults of all species 14 d after the RH treatments increased within the 75% RH Control arenas. Different species and life stages responded differently to 43 and 50% RH, as time to kill all stages of the four psocid species was 8–12 and 10–16 d, respectively. Results indicate that using a specific RH environment may be effective in psocid management.

Prevalence and abundance of insect pests in stored pulses collected from two local markets of Dhaka city

Prevalence and abundance of stored grain insect pests in four varieties of pulses i.e. Lens culinaris, Pisum staivum, Cicer arietinum collected from two markets of Dhaka city were recorded. Nine species of insect pests, viz. Sitophilus oryzae, Tribolium castaneum, Callosobruchus chinensis, C. maculatus, Rhizopertha dominica, Oryzaephilus surinamensis, Liposcelis entomophila, Sitotroga cerealella, and Formica sp., were recorded throughout the study. The percentage of weight-loss was higher (7.54) in those pulses which were highly infested by pests. Highest pest population was observed during May to June (753). However, Sitotroga cerealella were found only in November to December of the study period. The maximum species richness (7) was observed in Green gram and Chickpeas samples, but the minimum species evenness was observed in Green gram (0.6969) and maximum in Red lentil (0.9886). Jahangirnagar University J. Biol. Sci. 8(1): 75-82, 2019 (June)

Psocoptera (Psocodea) in Spice and Medicinal Dehydrated Plants Sold in Bulk in a Big Metropolis in Brazil

ABSTRACT In Brazil, the production of dried herbs and condiments is on a smaller scale than that of its other agricultural sectors; however, it has been growing and attracting new producers, driven by the stimulus to provide healthy and gourmet foods. Insects in the order Psocoptera may cause loss of quality in such dried foods, and because of their small size, these insects can be easily transported by commerce. No information is available on how these insects may be entering Brazil via the importation of dehydrated products or how they may be exported with the increase of Brazilian dried food production. To examine these issues, 10 sites offering foods sold in bulk within the city of São Paulo, Brazil, were chosen. At each food site, the same 20 species of aromatic spice and medicinal dehydrated plants were purchased. In the laboratory, they were analyzed for the presence of insects immediately after acquisition. After removal of nymphal and adult psocopterans, the plants were kept in vials under environmental conditions to be investigated 40 days later. Psocopterans were found in 12 of the 20 dehydrated plant species. Eleven psocopteran species were recorded, including six species of unidentified Liposcelis. Liposcelis bostrychophila (Badonnel) was found in all samples with the presence of insects. The other frequent species were Liposcelis entomophila (Enderlein) and Lepinotus reticulatus (Enderlein). Lepinotus reticulatus constitutes the first record in Brazil. In total, 1,021 insects were recorded in the evaluation right after purchase, and this number grew to 3,734 individuals recovered 40 days later under laboratory conditions. The data show that in a relatively short period of storage, a population increase occurs that may cause loss of product quality and a decrease in organoleptic properties. Thus, it is necessary to have greater surveillance of the products so that consumers have access to quality dehydrated foods.