Predation of Florida red scale Chrysomphalus aonidum (L.) by the metallic blue ladybeetle Curinus coeruleus (Mulsant)

Florida red scale, Chrysomphalus aonidum (L.) is a species of armored scales, which attacks citrus crops. Biological control, particularly ladybeetles, are critical for its management in citrus production systems. We evaluated predation of C. aonidum by adult and larvae (3rd–4th instar) of the metallic blue ladybeetle, Curinus coeruleus. C. coeruleus were tested against C. aonidum in three separate treatments on Valencia orange leaves in Petri-dish arenas (1) individuals with armor intact, (2) individuals with armor removed, and (3) mix of individuals with armor intact or removed, to determine if armor inflicts distraction to predator consumption of scale and impact. Within 24 h of exposure to C. aonidum, adult beetle consumption rate averaged 64–68% in the two treatments containing all or half of the individuals with armor, compared to 100% in the treatment with armor removed. The consumption rate in the former two treatments increased to 83–89% within 72 h. Larval consumption of C. aonidum with armor intact was 25% at 24 h and 41% at 72 h, compared to 92–100% in the treatment with armor removed. The adults resulting from the larvae developed on C. aonidum with the armor intact or between the diets of armor intact or removed consumed more scales without armor than with armor. Significant consumption of C. aonidum by adults and larvae of C. coeruleus indicates that it is an efficient predator of this pest species. These novel findings suggest that this predator could be useful for suppressing C. aonidum populations in citrus production systems, particularly in habitats where both species are established such as Florida.

Bionomy of small spruce bud scale, Physokermes hemicryphus (Dalman) (Hemiptera: Coccidae) in Serbia

Small spruce bud scale, Physokermes hemicryphus (Dalman) (Hemiptera: Coccidae), is a Holarctic, oligophagous species developing on plants of the genera Picea and Abies (Pinaceae). It is a serious pest of Picea abies in Serbia, which causes drying and falling of needles, branches and even drying of entire plants. A study of the bionomy of Ph. hemicryphus was carried out at five locations in Serbia in 2016 and 2017. Ph. hemicryphus was found to develop one generation annually and to overwinter as second-instar larvae on spruce branches. Adults emerge at the beginning of April and oviposition takes place at the beginning of May. Larvae hatch in the second half of May; during summer they feed on spruce needles and moult into second-instar larvae in September. Scale populations are controlled by a number of natural enemies. Five species of parasitoid wasps were reared: Coccophagus lycimnia (Walker) (Hymenoptera: Aphelinidae), Metaphycus unicolor Hoffer, Microterys lunatus (Dalman), Pseudorhopus testaceus (Ratzeburg) (Hymenoptera: Encyrtidae) and Pachyneuron muscarum (L.) (Hymenoptera: Pteromalidae), as well as five predatory species: Anthribus nebulosus Forster (Coleoptera: Anthribidae), Exochomus quadripustulatus L., Scymnus abietis Paykull, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) and Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). The most efficient parasitoid of Ph. hemicryphus was P. testaceus, reducing scale populations up to 28.97%, while the most efficient predator was A. nebulosus with an efficacy of up to 51.72%.

Differential Efficacies of Nomuraea Rileyi and Isaria Fumosorosea on Some Serious Pests and the Pests’ Efficient Predator Prevailing in Tomato Fields in Egypt

The efficiency of the two microbial control agents Nomuraea rileyi and Isaria fumosorosea, were evaluated against Bemisia tabaci and Myzus persicae pests in tomato cultivations The safety levels of the agents, to the predator Coccinella undecimpunctata, were also studied under laboratory and field conditions. Results showed that under laboratory conditions, LC50 values for N. rileyi and I. fumosorosea were 103.7x104 and 139.4x104 spores/ml against B. tabaci, respectively, while the corresponding values for M. persicae were 89.1x104 and 149.8x104 spores/ml, respectively. Under the field conditions, the percentages of infested plants with B. tabaci and M. persicae were significantly decreased after treatments with both fungi as compared with the corresponding controls. At the El-Esraa farm (Nobaria region), the weights of the tomato yield were 2,417 and 2,911 kg/feddan when I. fumosorosea and N. rileyi were applied respectively, as compared with 2,010 kg/feddan in the corresponding controls. The corresponding yields in El-Kassaseen were 2,699 and 2,999 kg/feddan, respectively, as compared to 1,990 kg/feddan in the control. The present study showed that C. undecimpunctata exhibit relatively high and reasonable resistance to N. rileyi and I. fumosorosea at the highest lethal concentration (1x108 spores/ml) for both tested preys.

The influence of predator threat on the timing of a life-history switch point: predator-induced hatching in the southern leopard frog (Rana sphenocephala)

We tested the hypotheses that potential egg predators, crayfish Procambarus nigrocinctus and dytiscid Cybister sp. larvae, would accelerate the timing of hatching and that a larval predator, dragonfly naiad Anax junius, would delay hatching in the southern leopard frog (Rana sphenocephala). We also tested the hypothesis that differences in response would be proportional to predator lethality. Our results indicate that our hypotheses were partially supported. The presence of an efficient egg predator (crayfish) induces hatching faster than a less efficient predator (dytiscid larvae). However, the presence of a larval predator (naiads) did not delay hatching. Eggs that developed in the presence of egg predators produced hatchlings that were shorter (total length) than those reared in the presence of larval predators or those reared in the absence of predators. We suggest that earlier hatching times should decrease vulnerability to egg predators but result in shorter hatchlings.

Predation by Hunting Spiders on Citrus Leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae)

Feeding efficiency of the three species of hunting spiders, Chiracanthium inclusum Hentz, Hibana velox (Becker), and Trachelas volutus (Gertsch), was investigated in laboratory, greenhouse, and field-cage experiments. Results of the laboratory feeding efficiency tests showed that the predation rates of these hunting spiders can be ranked as follows: H. velox > C. inclusum > T. volutus. A similar trend of predation rates was obtained from the feeding efficiency test under greenhouse conditions. The predation efficiency of H. velox was further tested in a field-cage experiment because it was found to be a more efficient predator than C. inclusum and T. volutus from the laboratory and greenhouse feeding efficiency tests. The results of the field-cage experiment indicated that as the population density of the citrus leafminer increases, the number of citrus leafminer consumed by H. velox also increases. In addition, significantly more citrus leafminer larvae were consumed when two to three H. velox were present inside the cage than when only one H. velox was present.

Natural Enemies of the Pear Leaf-curling Midge, Perrisia pyri, Bouché (Dipt., Cecidom.)

There are three main parasitoids and one very efficient predator associated with Perrisia pyri in France. Of these, at least during July and August, the predacious Capsid, Pilophorus perplexus, achieves the greatest destruction of midge larvae.The two species of Platygasterids differ in several points of ethology from the species of the same or adjacent genera attacking Contarinia pyrivora. They are both egg-parasites, developing very slowly in the midge larvae during the growth of the host. Their action appears to be largely complementary, corresponding to morphological differences in the organs of oviposition. Their life-history is very imperfectly known.Torymus abbreviatus is extremely efficient. Its eggs are laid within the curled leaf among well-grown midge maggots on which the larva lives as an ectoparasitoid. The duration and location of the pupa stadium is unfortunately not yet known.Some half a dozen other enemies were found to play a less important part than the preceding.