Spinach leaf miner

See Chrysanthemum leaf miner Holly leaf miner Spinach leaf miner. 

These crops are relatively trouble-free, although some tend to bolt in adverse conditions. Beet leaf miner (see above andp.323) has little effect on beets, but it can spoil leaf beet and chard. Downy mildew can be a problem on young spinach when the air is moist. 

Baby leaves and herbs are attractive to a wide range of pests especially aphids, leaf miners, caterpillars and slugs. The contamination of the crop with insects is also a commercial issue. Seedling diseases can affect the crops such as Pythium and Rhizoctonia but the main disease is downy mildew which can lead to complete crop loss if untreated. Resistant lines are available for some of the larger volume crops like spinach but downy mildew evolves new strains rapidly and plant breeders are always playing catch up . 

Mineral deficiency strongly affects the development of leaves and of the photosynthetic apparatus. We were interested to know whether carbon flux is more restricted in mineral deficient leaves by the thylakoid system or the Calvin cycle. Spinach was grown under mineral deficiency as shown in Tab. 1. Leaves of different age were detached and photosynthesis and F was measured. Rates of photosynthesis were on a unit leaf area basis consistently higher in the control leaves than in leaves deficient in phosphorus, sulfur or nitrogen. Sulfur and old nitrogen deficient leaves were chlorotic. F was increased under all deficiency conditions and particularly so in old leaves of phosphate and nitrogen starved plants and in young leaves of sulfur-deprived plants. The increase in F clearly correlated with the development of pronounced deficiency symptoms and reduced rates of photosynthesis. The data indicate that mineral deficiency introduces flux limitations in the Calvin cycle. 

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