Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) is an important type of thrip and a polyphagous pest, which poses a serious threat to many crops, especially those in tropical regions of China. Its feeding behavior and the damage caused vary among different host plant species and are affected by ambient temperature and plant nutrients as well. The digestion rate is an important index for directly observing the digestion process, but there have been no studies directly measuring the digestion in thrips under the influence of different temperatures and host plants. Here, the digestion rate of F. intonsa was assessed by using a molecular diagnostic tool. We also determined the nutrient content in three host plant (mango, cowpea, and pepper), including soluble proteins, free fatty acids, soluble sugars, and water. The results showed that the high and low temperatures (16 °C and 32 °C) both seemed to accelerate the digestion of F. intonsa compared to the optimal temperature (26 °C) and the protein content of plants played an important role in the digestive response of F. intonsa to temperature changes. The findings can help reveal the feeding damage caused by F. intonsa to different plants and help to better understand its feeding ecology, according to its interaction with the host plant.

We designed a series of semifield experiments and two types of nylon cages to evaluate the control efficacy of Spalangia endius Walker in the field and to verify the possibility of using S. endius for the control of Zeugodacus cucurbitae (Coquillett) pupae. More hosts were killed by S. endius at higher parasitoid–host ratios. The effectiveness of S. endius was highest at a parasitoid–host ratio of 1:10, which caused 50.33% and 33% mortality in enclosed and semiopen conditions, respectively. The adult parasitoids supplemented with honey solution or water survived to 7 or 5 days at most, respectively. S. endius showed a low control efficacy for Z. cucurbitae pupae in the field. However, combined with the natural mortality of pupae and the effects of other natural enemies, the mortality of Z. cucurbitae pupae exceeded 85%. Thus, S. endius may help control Z. cucurbitae pupae in the field, but other control strategies need to be applied to kill the pupae in the soil which S. endius cannot reach and to control any remaining adult Z. cucurbitae.

The cowpea thrips Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae) exhibited unexpected aggregation on flowers of the non-host Baccaurea ramiflora Lour. (Malpighiales: Phyllanthaceae), suggesting floral volatile-mediated attraction. We systematically investigated this phenomenon through: (i) GC-MS identification of B. ramiflora floral volatiles; (ii) electroantennographic (EAG) and olfactory assays; and (iii) field trapping experiments. Both the flowers of B. ramiflora and their headspace extracts exhibited significant attractive effects on M. usitatus. Five key volatile organic compounds were consistently detected: linalool, 2,4-decadienal, trans-2-decenal, (Z)-β-ocimene, and trans-2-undecenal. The antennae of M. usitatus demonstrate distinct sensitivities to different volatiles, with the appearance of their EAG response peaks being affected by the dosage levels at which these volatiles are applied. The olfactory responses revealed that linalool (100 to 10000 μg), 2,4-decadienal (10 to 10000 μg), and trans-2-undecenal (1000 to 10000 μg) attracted M. usitatus. Trans-2-decenal attracted M. usitatus at 1000 μg but repelled at 10000 μg. (Z)-β-ocimene repelled M. usitatus at doses ranging from 10 to 10000 μg. Field trials confirmed 2,4-decadienal (10 to 100 μg) as the most effective attractant. These findings support the development of a 2,4-decadienal-based semiochemical strategy for sustainable M. usitatus management in cowpea production systems.